Tube amp sitting unused for a long time

 I'm considering an estate sale Scott 299 that has sat unused for  long time- possibly several years. The seller claims not to have powered it up so it is 'as-is'. I don't work on electronics myself so perhaps I should pass and pay more for one that is tested and working.But the price is tempting.
1.  Can I power it up or should I take it to a tech who I assume will use a Variac?
2.  Should I expect degraded  sound quality and performance because the amp from lack of use? I heard the capacitors need to 're-form' and this can take several hours or days. True?
3. What  should I budget $$ for labor and expenses- ball-park?

 I have such find memories of the warm sound of tube amps and wan tot get back into them

Thank you!

This is a very nice amp and should NOT be turned on without a variac. I had one, enjoyed it very much and is worth having a tech go though it. A parts unit recently sold on eBay for $250.00 and a nice one $995.00. I suggest you buy it and contact Pat @ Classic Tube Audio for a checkup and cap replacement. I think I paid $180.00 or so for his services, well worth it.
There's a cheap why to start this up without a variac. You use a 40 watt incandescent light bulb.

It has to be wired in series with the AC power cord. By that I mean that if you turn on the amp, the current for the amp should also flow through the lamp. The lamp should not be able to light up if the amp is not on.

Then you remove all the tubes and start up the amp. The light bulb will light up, limiting the current so as to prevent damage to the caps. As the caps 'form up' the bulb will go out. When it is no longer lit, then the amp can be safely operated. Put the tubes in it and see how it does.

If the bulb does not go out after an hour, the caps are shot and should be replaced before the amp is used.

Now its a simple fact that the amp is ancient, and the caps are probably shot as a result anyway. So this method or that of a variac is probably moot as that service should be performed. If not the power transformer can be destroyed and that will be a very expensive and hard to find part, not to mention a bit of a tragedy.

Expect to pay between $200 and $350 to get the amp serviced out. It is worth it.