I use SeaFoam as a solvent, because it is a solvent. I found a supply for $5.99 a pint, but it runs close to $10 most places. A pint lasts a long time. Again, I don't want to make anyone use it, but if you have an old barn find you're trying to get running a few cents worth is worth a try. I feel the same way about starting fluid, even though it can hurt you and blow up an engine. People probably felt the same way when washing with soap was the new fad.

My Walmart years ago for some reason was getting rid of a lot of the liquids in the auto section.  They had the solvents, oils, and miscellaneous cleaners all marked down a lot.  I found the autoshop manager and told him I'd give him $50 for the whole thing.  He said $100 and we settled on $70.  Good deal for me.  The Walmart standard price collectively on all that stuff was over $300.  

The lot included Seafoam, Berryman's Chemtool, Rislone, Gunk, synthetic 2-stroke oil, and lots of other stuff.  Most of it is gone now, but I'll admit the seafoam worked pretty well.  The Berryman's was the most powerful, though, and don't you dare ever let it drip on any paint.  What I learned from the comparison of actually using the stuff was that seafoam is literally nothing more than an overpriced solvent.  A strong solvent, yes, but nothing exceptional except for the exceptionally insulting price.