Seafoam is distributed by NAPA in the US. The parts america stores (Such as Shucks) only carry the seafoam transmission treatment. If you have a NAPA near you, they will either have it on the shelf, or will be able to get it from the warehouse the same day. My local NAPA store can't keep it on the shelf!
Seafoam saved me about $350.
On my cage, (1997 Nissan altima with 100k miles on the clock) the check engine light came on and it started idling rough, and guzzling gas. I burped the computer, and it gave me an EGR code. So, I pulled the EGR valve off, and cleaned it up as best as I could. Put a new gasket on, and torqued it down. Light came back on, and the engine was running rough as ever. So, since my emissions test was coming up in a few weeks, I needed to get it fixed. I called the local "Greg's Japanese Auto" shop, and they quoted me $250 in parts, and $100 in labor to replace it. I figured I'd give seafoam a try, so I dumped a can in my tank, filled it up with Tier 1 gasoline (chevron) and took a 200 mile road trip into the mountains. Right about the time the empty light came on, the Check engine light turned off, and it's been 6 months. Car runs like a dream. I treat her to a can every 6 months, same with the bikes.