IMHO there's no doubt you need to protect your body from any possible injury, but I do believe you don't have to spend top dollar to get it (protection).
Companies like Alpinestars charge top dollar cause of their name, I know there's others out there that offer the same protection and in some cases better.
IMO the thing to do is go and try as many as you can and make an educated decision and what feels best for you.
Bottom line is, you don't have to break the bank to get good protection!
Oh yeah, and be safe!