The trap a lot of people fall into is paying full price for those budget carriers by booking late or not reading the fine print. That said, the earlier answer about date flexibility is spot on - it genuinely makes the biggest difference, way more than which airline you pick. If you can fly midweek instead of weekends, you'll save substantially. The sneaky fees thing is real too, but most of these airlines have gotten slightly more transparent about what they charge, so it's easier to compare the actual total cost now.
Beyond Ryanair and Easyjet, I'd also look at Wizz Air if you're heading to Eastern or Central Europe - they've been competitive lately and their fees structure feels a bit less painful than some others. Vueling is worth checking for southern routes. The key isn't picking one airline and sticking with it; it's comparing the full price (including checked bags, seat selection, all of it) across a few options for each leg of your trip. Tools like Skyscanner or Google Flights let you see multiple carriers at once, which saves time.
One thing that actually helps is booking your flights separately instead of trying to find one cheap connection that forces you onto a specific route. Sometimes two separate short hops are cheaper and give you more flexibility if plans change. Also, if you're backpacking for two weeks, look into whether rail passes make sense for some segments - sometimes a budget flight + a train journey actually works out cheaper and less stressful than dealing with multiple flight bookings.