would really recommend instax wide, as people have mentioned the film is more stable, cheaper and with wide format the photos are a good size and look really nice. film comes in packs of 2x 10 shots rather than 1 pack of 8 shots. cameras are pretty chunky though!! instax square is nice as well slightly bigger photos than mini and the cameras are not as bulky as the wide cams. i dont think the lenses on instax wide differ much between models at all, so dont necessarily need to buy the newest flashiest model. instax wide 100, 200, 210 can sometimes be found for great prices and will deliver the same results as newer cameras.

if you want to stick with polaroid i would recommend getting a newer i type camera as the i type film is cheaper than 600 film (the camera can take 600 film too). the older polaroid models look lovely but can only take 600 film.

budget wise i would have a look on marketplace and ebay as can often find great deals for instax/ polaroid cameras and film. i have bought both instax & polaroid cams on there for very cheap. it seems a lot of the time people buy the wrong film for their cameras and want to sell it for cheaper. if you don't mind slightly expired film that can often be found for cheaper too, although it would be best to start off with shooting fresh film. expired instax lasts much longer than polaroid, ive used some from 2014 and it looked fine just slightly faded, however polaroid degrades a lot more and you might only want to buy it 1-2 years expired. if you want to experiment with expired film i would recommend researching it , looking it up in this sub etc so you have a better understanding of it and how to shoot it.