Re: "Sleeper" guitar -
Cheap sleepers:
My G&L Tribute Rampage takes the prize. It was $330 shipped with a nice quality G&L gig bag, and it's 90 percent good as any U.S.A.-made Fender I've ever owned, short of my handful of Custom Shop models. That 10 percent is accounted for only by the somewhat cheap tuners...but it has a locking nut, so who really cares anyhow? It has near-perfect fretwork, absolutely perfect finish work, beautiful craftsmanship and setup, great sounding pickup, a Kahler Hybrid (a perfectly respectable piece of hardware IME), wonderful extra wide nut width (1-3/4") and 14" radius, nice and smooth full-sized Alpha pot (unlike those tiny ones that usually come in Asian imports, and that always crap out on me), beautiful ebony fretboard, and even some figuring on the maple neck! The only thing I might change on it is the lack of a tone pot. I might go ahead and convert to a full-on three-knob G&L PTB system some day, but that's it. That's about a $20 job, bringing the cost of the guitar up to $350. Short of getting something for free, you can't beat that bang for the buck IME.
Another one would be my MIJ Epiphone '61-style SG. The thing was better made than any modern Gibson SG I've ever played, and being an MIJ, it had the open book headstock. The only thing it lacked was quality electronics. I spent $400 on the guitar and shipping, and put about $200 into electronics upgrades ('57 Classics and good pots/caps, jack, switch, knobs, etc). $600 for that guitar was an insane bang for the buck. Last year I sold it to my bandmate for $500, just to pare down my collection a bit. If I didn't have a '68 Standard, I would never have sold the Epi, though. It was every bit as good as the '68...which is kid of why I decided to sell it in the end. I didn't need two practically identical guitars, so I stuck with the antique one that has sentimental value.
$100 for my used Bronco bass in perfect condition was a HUGE bang for the buck. It's one of my favorite basses on the market, and it needs absolutely nothing more than a nice set of strings and a setup IMO. I sold mine last year while paring down, but only because I have a '76 Musicmaster Bass, which is practically the same thing, only "The Real Deal," and with tons of sentimental value.
Expensive, but enormous bang for the buck sleepers:
My G&L prototype Legacy for $1,000 total is perhaps my own personal "deal of a lifetime." The guitar is one of the best all-around axes I've ever played. It has a western sugar pine body and neck. It was made as a prototype for a possible Brad Whitford signature model, but the model never got put into production. So not only is it a completely and truly AWESOME musical tool, but it's literally one of a kind.
My G&L Legacy Rustic "Blackie" color scheme was expensive at $1,440, but even so, it's one of the best bangs for the buck I've ever got. It's easily at Fender Custom Shop level. Along with the prototype above, the Rustic is also among the finest guitars I've ever owned, and again, pretty darned rare. Rustics are rare guitars in general. They are produced in very low numbers. I've only ever seen about a dozen Legacy Rusics for sale. But it's even more rare to see a Legacy Rustic that isn't Blonde or Lake Placid Blue. I've only seen three that aren't one of those two colors (two black, including mine, and one 2TSB).
My Custom Shop Esquire was expensive, but god damn if it isn't the best guitar I've ever owned, in just about every way. And through some bizarre series of flukes, coupled with my nearly lifelong relationship with a certain local guitar shop, I got it for dealer invoice plus tax and shipping back in 2003. I think it ended up being something like $1,600 +/- out the door. That sounds painful, but I consider it a real bang for the buck, considering how flat out great it is.