Here in Dallas, TX... we pay around $50-$70 for sprint tri's. That can be a pool swim or lake swim.
If you aren't going to compete more than 3 times this year, you might as well pay the USAT "dues" when you sign up for your tri's.
Honestly, with a basic membership, you just get a cool tag to hang on your key ring and a kind of lame magazine every 2 months (? or more?). Not really worth the extra moo-laa if you ask me.
Maybe I don't know what all membership has to offer... but I think that's it.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"