The best one coat wax is Meguiers cleaner/wax. It has paint cleaner in it that will help fill in and smooth out swirls and it still leaves a protective finish. I use it a lot on my Stealth. And its in your budget at $5 a bottle.
If you use a cleaner it will help smooth out the swirls. A polish helps fill in swirls and give a wet look to the paint. Wax only protects the paint, although a lot of waxes contains some polish.
later,
Curt
http://www.mn3s.org