Alan, That's a great way to save money. Most time is spent in cutting and layout, measureing, adjusting etc. The finish welding goes quickly.
It is interesting that y'all are not getting to keep the "drops" when you pay for a full length and a cut. You should get to keep them. Shop around and haggle. Prices are negotiable.
I'm surprised none of y'all woodworkers have horizontal bandsaws. I did without one for years until my woodworker friend sold me a small Delta he had. They work great on metal. I wish I had bought one sooner.
Abrasive "chop saw" blades do have some flex to them. Are you noticing any angled cuts that make the mitered 45's not fit together quite right. You can adjust for that or fix it later with a grinder.
The carbide tipped metal blade saws are the Cadillac. I have not sprung for one yet. A good one will run you about $450 and the blades are about $200. The chop and band saw do good enough to keep me from buying one.

I didn't think I'd ever get a chance to disagree with Andrew (or be brave enough to) but I sure had bad luck with the cheap grinder from HF. I swear by my $49.99 Craftsman. It's the best price/value I've found.
D. Tillery