Advice on a 12 footer
You should be able to find nice 12 to 14 foot boats in the $500 to $600 range. Boats like that are a great way to learn to sail. One minor point is that region is notorious for very light air during the season when the air is warm enough to sail an open boat. As a result you may be better off with something a little larger that can take an outboard to get you home when the wind dies.