There aren't many collectibles that are cooler than single-signed baseballs of U.S. Presidents. And on the heels of Super Tuesday, single-signed balls of some of the hopefuls continue to heat up. There was a John McCain that ended last night (now that's planning) for $305 and it featured a horrible scan so there's potential for those to sell quite a bit higher, especially after he distanced himself from the competition and looks like a shoe-in for the Republican nominee.

McCain baseballs were selling for around $100 a week ago and for as little as $30-40 a month or so ago when it seemed like he had little chance of winning. In fact, in late Dec. a lot of five single-signed McCain balls sold for only $120.

Barrick Obama single-signed balls have been an interesting collectible since he emerged as a leading Democratic candidate. Whether it's this presidential campaign or a future one, collectors feel like he'll be a major name for the next couple decades and are willing to spend more. His baseballs have been solid around $200. A quick bit of advice from surfing around eBay for a bit, beware of any non-authenticated Obama ball because most of them look like pretty bad fakes. It will be interesting to see what this PSA 10 ball goes for in Mastro's Classic Collector auction. There's also a pretty cool lot coming up in R&R with McCain, Obama and Rudy Giuliani that should go pretty high.

Hillary Clinton's single-signed balls are consistently higher priced than McCain or Obama, possibly because many people consider her the favorite and are holding on to them. As far as I've heard, she also doesn't sign as freely as she once did. A nice Clinton ball will cost you $400-$500 at this point. Judging by the last night, these are the only three that I need to mention.