It’s best if you are still learning or progressing to own your own board. All your receptors are having enough problems ‘learning’ the new skill, a degree of consistency helps.
Snowboards vary such a lot, variable flex, variable sidecuts, not to mention the new trends with variable rockers and cambers.
If you only go once or twice a year for a week, then it still works out (given the board always has some residual value)better to buy than rent.
Boots, agreed first purchase and change them if they go too soft and lack ankle support and/or you start getting heel lift.
Right now there are lots of shows where there are inevitably deals, wether you’ll get a board and bindings for your target budget without buying s/h off ebay I’m not sure, funnily enough I’m changing mine this year and it’s about to go on ebay, but it’ll be board only, I’m keeping the bindings, they’re step in rapid fires from Shimano, you can’t get them anymore and I’m a lazy rider, like to ride on and off my lifts.