What can the foamy looking stuff in the radiator be? Shop said I had to replace the engine head gaskets. Gotta be big bucks. I suck at troubleshooting but good at fixing it. He refused to flush radiator and said he was afraid of blowing the gaskets out. Is he taking me for a ride?

Pull your oil dip stick. Does it look like it has chocolate milk on it? If so, that is a sure sign of a blown head gasket.
If it doesn't look like chocolate milk, don't ever go back to that mechanic.
The red radiator coolant is notorious for foaming if there is any air in the system. More than likely that will be your problem.
Park your car level and with the engine at operating temp slowly unscrew the hex bolt on top of the t-stat housing until fluid starts to leak out. Once fluid starts leaking out, tighten the hex bolt, just be careful and don't tighten it too tight.

Oil looks good. Just the crap in the radiator. Should I see blow out around the top of the engine if the gaskets were no good?

not if it was leaking into the motor.

What engine do you have? It could be an intake gasket leak on a 3100 as well. Be sure to check the bottom of your oil cap and pcv valve (on 3100) as well.

It's Definitely, sounds like a Problem of a Blown Head Gasket, that I have seen on My previous car. The Mechanic, claimed that the Foaming was from the AntiFreeze mixing with the Oil & the Result of it All, was Immediate Overheating(5-10 mins. of Driving) & Lack of Power.

At the Time(3yrs. ago)...it ran Me, $585.00 to have it Fixed at the Dealer. Luckily, the Extended Warranty was still Active. So, it saved Me some $$$$.

But, at this Time...without the Warranty, it could even be More Expensive. But, as Someone here Suggested to Me, when I was Inquiring on My GP problem...either, "Try a another Mechanic Shop, but stay away from the Dealership".