Budget airlines can be a real money saver (especially if you book with the best budget airlines). Some of the companies, like the new LEVEL with budget flights to Barcelona and Paris, are great to fly on. Others, not so much. But there’s one thing that’s pretty much unavoidable no matter which budget airline you take: baggage fees.

Some people have a lot of baggage, and that can add up. If you’re one of those people, try to avoid any unwanted surprises by checking the different airlines’ fees. These are the most popular domestic budget airlines in the US, ranked by baggage fees.

1. Southwest

Free baggage: One personal item, one carry-on bag, and two checked bags.

Baggage fees: Every checked bag after the second is $75 each.

2. JetBlue

Free baggage: One personal item and one carry-on bag.

Baggage fees: $30 for the first checked bag, $40 for the second. Blue Plus and Blue Flex fare options both include a free checked bag (one for Plus and two for Flex).

3. Alaska Airlines

Free baggage: One personal item and one carry-on bag.

Baggage fees: $30 for the first checked bag, $40 for the second, and $100 for each additional.

4. Allegiant Air

Free baggage: One personal item.

Baggage fees: Costs vary depending on your departure airport and are non-refundable. Carry-on costs range from $10 to $75. Up to four checked bags per person can be purchased, up to 40 pounds each. It generally costs $25 for a checked bag if you buy it when booking, $45 after booking but prior to check-in, and $50 if you check your bag at the airport.

5. Frontier Airlines

Free baggage: One personal item. If you purchase one of the two bundled ticket options (the perks or the works), one carry-on and one checked bag is included.

Baggage fees: Costs vary depending on when you purchase and are non-refundable. For a carry-on, it’s $30 to $35 when purchased at time of booking, $40 when purchased after booking but prior to check-in, and $45 at the ticket counter. For checked bags, it’s $30 for the first bag ($45 for the second and $80 for the third) when purchased while booking, $40 for the first bag ($45 for the second and $80 for the third) when purchased after booking but prior to check-in, and $45 for the first bag ($50 for the second and $85 for the third) when purchased at the ticket counter. Bags are $60 if you’re forced to check it at the security gate because of size.

6. Spirit Airlines

Free baggage: One personal item.

Baggage fees: Costs vary depending on when you purchase and are non-refundable. For a carry-on, it’s $37 when purchased at time of booking, $45 after booking but prior to check-in, $55 at the ticket counter, and $65 at the gate. For checked bags, it’s $32 for the first bag ($42 for the second and $87 for the third) when purchased at time of booking, $42 for the first bag ($52 for the second and $97 for the third) after booking but prior to check-in, and $52 for the first bag ($62 for the second and $102 for the third) at the ticket counter.

Photo: Martina Badini/Shutterstock

In general, international flights on budget airlines are a little more lenient when it comes to carry-on and personal item fees. Checked bags, however, will cost you. These are the most popular domestic budget airlines with flights to and from the US, ranked by baggage fees.

1. LEVEL

Free baggage: One personal item and one carry-on bag.

Baggage fees: Costs vary depending on when you purchase and are non-refundable. It’s $45 to $55 for the first bag ($90 to $65 for the second) when purchased at time of booking, and $55 to $73 for the first bag ($165 for the second) when purchased at the ticket counter. Every pound heavier than 50 is an extra $13, or a flat $100 surcharge for bags over 50 pounds (23 kg) on flights to and from Barcelona.

2. XL Airways

Free baggage: One personal item and one carry-on bag. One checked bag if you purchase an Eco Plus level ticket.

Baggage fees: First bag is $50 when purchased through a call center or online, $75 at the ticket counter ($81 and $115, respectively, for additional bags).

3. Norweigan Air

Free baggage: One personal item and one carry-on bag.

Baggage fees: $75 for an oversized carry-on at the gate on domestic flights, $120 on international. For checked bags purchased at the airport, the cost is $65 for direct domestic flights ($100 international). For connecting flights, checked bags purchased at the airport are $130 for a domestic connection, $165 for a domestic to international connection, and $200 for an international to international connection. Norweigan has a four-tier table to calculate baggage fees purchased at time of booking, which can be found here, that varies on departure and arrival location. Prices vary from $13 to $180.

4. Westjet

Free baggage: One personal item and one carry-on bag. First checked bag free for EconoFlex, and second checked bag free for Premium and Business.

Baggage fees: $36 for the first bag, $59 for the second, and $100 to 4118 for the third and fourth bags. Overweight bags (51 to 100 pounds) and oversized bags (63-80 inches) are $100 to $118.

5. easyJet

Free baggage: One carry-on bag. One personal item for Flexi, Upfront, and Extra Legroom customers, as well as easyJet Plus cardholders.

Baggage fees: Costs vary depending on when you purchase and are non-refundable. Price ranges from $8 to $42 for bags up to 33 pounds, and it’s only available for purchase online. For bags up to 50 pounds, the price ranges from $12 to $50 when purchased online and $60 when purchased at the ticket counter. The cost for overweight bags is $15 per 6 pounds.

6. Swoop

Free baggage: One personal item.

Baggage fees: Costs vary depending on when you purchase and are non-refundable. Carry-on bags within Canada cost $40.25 when purchased at time of booking ($46 for flights outside of Canada), $46 after booking but before check-in ($51.75 for flights outside of Canada), $51.75 during online check-in ($57.50 for flights outside of Canada), $57.50 at the ticket counter ($63.25 for flights outside of Canada), and $80.50 at the gate ($86.25 for flights outside of Canada).

Checked bags cost $46 when purchased at time of booking ($63.25 for the second and $100 for the third), $51.75 after booking but prior to check-in ($69 for second, $120 for third bags), and $57.50 at the ticket counter ($74.75 for the second and $126 for the third).