Insulation - either Dynamat or Insul-Shield tho the latter seems to cater more towards the rod market.

Paints - I like Southern Polyurethane's sandable epoxy primers, Evercoat Rage fillers and putty, DuPont base and Southern's Universal clear (see my avatar car above and elsewhere on this site). PPG has some problems with their epoxies (washes off with lacquer thinners). DuPont epoxies dry as hard as a rock, but they are good if you don't have to do any body work filler work on top of them and can BC within 24 hours. DuPont, PPG, Kirker, R-M, Sherwin Willims, Ditzler, Martin Senour(NAPA) all have good to excellent base and clear coats.

Cheap paints - that's what they are tho they may just be a major's second or third lines.

Southern (SPI) is relatively inexpensive as there is very little advertising though they don't have a multitude of colors. One nice thing, customer service. You have a problem and call - you talk to the owner or you join their forum and discuss.