I've had rebuilt calipers from the parts store that still dragged and I had to rebuild them again myself (the part store didn't have another one in stock).

I get some seals before I take calipers off just to have them if needed. Rock auto has the seals AND clips dirt cheap, like $4 vs $100 to fix one side. In the mean time just keep topping off system - brake fluid is also dirt cheap.

When you take the caliper off pop out the piston using the brake pedal and have a look at it.If it's not pitted badly, smooth it out with some fine sandpaper and water.
Lube it up with brake fluid and put it back together with a new seal. In most cases that works, unless water has been built up in the old brake fluid for years on end from not being changed.

You still have to do most of the work anyway, wrenching and bleeding (the brakes). I you need to you can always go to your local parts store for a caliper.

Another thing, get a turkey baster from the dollar store and clean out the old DIRTY brake fluid in the master cylinder. Just suck it out, replace, repeat... it won't put any air in the system and will get a lot of junk out. You can do this today.

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1985 300TD 1981 Scirocco 1.6D conv 1986 Golf 1.6D 2003 Golf TDI