"My understanding from something I heard in a podcast where Charter's president was interviews is, that they charge to repair the older guns (that predate the current incarnation of the company), and after that they are covered by Charter's warranty."
That's right, it's mentioned in their FAQ's. You pay to ship it to them, they'll repair it and ship it back to you for $49.95 + the price of the parts. The $49.95 covers all labor and return shipping.
So it would cost me $53.95 ($4 for the spring, if that's all it needs) to Charter Arms, plus the hassle and expense of shipping through FedEx. Iow, about $75 plus the packing and trip to FedEx. I did this with another gun earlier this year, and that's how it went.
Or I could do something stupid like order at least $15 ($16, 4 x $4) of parts and pay $8 shipping. $24 vs $75+.