Can you rent a helmet there?
If you're unsure that you'll continue track days (small chance - it's addictive), then I would just try to rent.
Otherwise, if you want to buy, the best thing to do is go to a local store and try them on. They all fit differently, and you really need to spend 20 minutes at a time with one on your head to determine if the particular pressure points are going to cause you any uncomfortableness at the end of a 20 minute session. There's a bunch of good entry helmets in the $300 range. It all depends if you want open/closed, style, color, etc. Just don't overlook the fit aspect you can only get when wearing a helmet for 20 minutes at a time inside the store. :biggrin: