Amazon in the U.S. has the Canon EF-S 55-250mm f/4-5.6 IS STM for as low as $130. It's the international version, so no warranty in the U.S. The normal price is $300, so no warranty seems like a reasonable tradeoff to me.
I purchased one a couple months ago, and I have to say I'm impressed. It doesn't match my 400mm f5.6L, but it's also much more compact and zooms. I find it quick to focus, and it does a respectable job with AF tracking. It's plasticky, so maybe not as durable as would be nice...but that price is hard to ignore. I took it to an air show in June (bigger birds than this forum is dedicated to

, and it did very well without being a pain to carry. Just choose an Amazon shipper to make returns easy, and make sure you get a good one. I've read the lens is somewhat prone to decentering issues, which my first copy suffered from. The second copy is awesome though.
https://www.amazon.com/dp/B00EP71ETU/ref=cm_sw_r_cp_apa_i_5-FADbRF02CW9