Not an expert on this, but AFAIK, private parties do not collect any taxes on auto sales in CA, but the seller has to report the sale to the DMV. Legally, CA will want you to purchase a Transfer Permit, but nobody ever does. Sales tax would be paid when you register the vehicle with the CA DMV, which you're not going to do. IF you were buying from a dealer and IF you planned to drive it off the lot, you would have to pay the CA taxes. Or optionally you could have it towed out of state. CA plates stay with the vehicle unless they're personalized. If the seller wants to keep the plates, your home state should be able to issue a temp tag that you can take with you. (This is what I would do if at all possible) You should be fine with the title, signed bill of sale, and proof of insurance as long as the CA registration is current, just don't drive around for days in CA with it and don't draw attention to yourself.
You would need to pay any applicable taxes in your home state when you register it.
98 Amigo, 2.2 5sp 4x4, 4.77 gears and factory LSD.
Power nothing - No power windows, no power locks, no power engine.
Even the hubs are manual now.
2003 Grille and headlight swap