don't forget that all models of PS3 are compatible with PSone games, not just those handful of launch models, those are quite power hungry and far louder than something like the ps3 slim... that said, you can get a ps3 now for chump change, picking one up from somewhere like CEX here will even grant you 24months warranty if you're worried about buying 10 year old hardware.
CEX site even lets you pick which model version of the ps3 you want to buy, for the most part their good at buying / selling the wrong things, if they make any mistakes from the online store you can return them to the retail place for a refund np.
Vita pretty much allows the playing of all PSone games too now, if you have it modded you can install a few great bits of software to allow you access to the full library of PSP and PSone games as well as the regular emulation fest of nes/snes/megadrive/gba and so forth
Fancy hearing me on an amateur podcast with friends gushing over one of my favourite games? https://youtu.be/1I7JfMMxhf8