I had my ARC VT100 Mk III re-tubed by ARC, but they sent the tubes to the local dealer, who did the actual retubing. (And, indeed, the dealer did a very responsible job, and found a minor biasing issue, which was fixed locally with a part supplied by ARC.)
If you do a lot of reading around, you will note that there is some controversy about re-tubing ARC VT100's. Note, for example, that Upscale Audio will not sell tubes for re-tubing VT100's. That, for me, has been a factor in deciding to let ARC do it, under warranty.
Also, I've had a fair number of tube amps over the last 25 years. I've sooner or later blown resistors in darn near every one of them (taking out a tube as well). (Well, in fairness, I should say I haven't done that to my BAT VK75, which I've had for a month.) That has caused me to lean toward relying on the manufacturer to provide replacement tubes, and to do repairs. It's a pain to deal with shipping (if you have to ship it in), but it's nice to have the manufacturer go over it and pronouce it ready-to-roll.
I understand the pain of paying more than you like, but there is a nice comfort factor there, too, it seems to me. Tube amps do a lot of hard work at high temperatures, and seem to me to deserve a little TLC.