Getting started with the basics - Part 1
Now that you're informed and ready to ride, you'll need a few necessary pieces of equipment. Don't go out and buy the best of everything, it will make you gun shy and make you wonder if you're doing the right thing.
Get a good pair of short boots ($100 - $175), half chaps ($90 - $150), good comfortable fitting jeans (Levi 505's) and a helmet ASTM/SEI certified ($150 - $300). Get everything fitting perfectly and color coordinated (black or brown); there is nothing worse than ill fitting equipment in this sport (you pay for what you get, but you don't want to look like a Sunday bike rider with no place to race).
Most of the time that's what I wear unless I have a lot of horses to ride, then I put on a pair of breeches and boots. Equipment (new and second hand) can be bought at local tack shops. Also look in horse catalogues of which there a handful (perhaps do this on the second round of equipment shopping after you have learned a little more about horse equipment and riding gear).