I've been wondering the same thing for a few years now.
Apart from doing zone system stuff and verifying if any part of the image will be out of the film's contrast range, spot meters don't have much of an advantage.
I use an incident meter for all the cameras that don't have a built-in meter and I train my eyes to detect what to do.
As for a meter, anything by Gossen and Sekonic that doesn't take a mercury cell is a winner in my book.
But if you want to get something cheaper, keep an eye for meters by Spiratone and Prinz. They're older and cheaper built than the big two, but since they aren't as popular you might get a chance at a good price. Also, Minolta used to make some good meters.