you could definitely get a used setup that is a few years old and wont run you much more than the price of a few rentals.
I was just at my local shop over the weekend and they had some used beginner setups for like 75$. find a shop that does gear swaps and you will def be able to find something as good as if not better than a rental setup.
edit: or you could just browse ur local craigslist for snowboarding gear. maybe you will luck out and get one of those moms cleaning out the house who puts up "nice snowboard for sale. there's a weird eagle painted on it - $100." that is if TimmyTard hasn't already jacked it. Search for his thread. he posts good deals he finds on craig's list.
case and point -