The tiny84 (or 841 - it's only slightly more expensive and has a way better feature set - but unfortunately only SOIC and smaller packages, no DIP) would be your go-to AVR here.Aliexpress IME is hit-or-miss for microcontrollers and IC's. There are some that you can get crazy cheap there, but most of the time, the deals don't end up being that good compared to the professional electronics supply houses (Mouser, Newark/Farnell, Digikey, etc) - Tiny84 and 841 are both like 70-something cents a pop from Mouser and Digikey. This is a stark contrast to passives, LEDs, and stuff like that, where aliexpress and ebay direct-from-china usually beat the western supply houses, often by an difficult-to-belive margin.
You may try www.tme.euIt has not everything and is not cheapest of all but it has decent prices, sells in small amounts and has reasonable shipping costs (at least to my country).
by the way which is the difference about packages between ssu and ssf?