Here's some amazing late summer deals on Frontier. Around 30 routes have dropped to just $20 each way ($39 roundtrip) for summer travel. Many more routes are available for under $100 roundtrip.
Availability is limited so you must be somewhat flexible to find the lowest price. Travel days will vary by route, but generally fares are available between August 14 and September 12. Pretty much all of these routes are only flown a few times each week so be sure to check out the specifics in the fare details on your route.
Tickets must be booked by 11:59 pm ET, on July 4, or before seats sell out.
Update July 6, 2018: It looks like the $39 roundtrip fares have stuck around this whole week and are still available today. Book now! These will likely be gone tomorrow.
Nonstop fares include:
These fares all work in reverse and there are many more routes between $57-$97 roundtrip as well. Check flights from your city to see all of today's finds.
Keep in mind that Frontier charges extra for any bags larger than a small personal item (small backpack, purse, etc.). Pack super light to get the lowest price. Checked bag fees for summer travel start at $30 each way. Larger carry-on bag fees start at $35 each way.