I've been using Carvins for years.
As far as the instruments and amps go I do not see them as "cheap", but "affordable".
I'll give you an example. Several years ago, when I bought my first Carvin guitar (a C66T), I ordered it with a mahogany body, quilted maple top, ebony fret board on a maple neck, abalone block inlays, Sperzel locking tuners and a Wilkenson trem. The total price? $300-$400 less than an off the shelf MIA Fender Strat. If you go with their kit version of the Bolt (Carvin's Strat) do the finish and assemble it yourself, you will save a $1,000 for a comparable Fender. Their guitars are made in San Diego (20 minutes from my house) and have a really high level of quality across the board.
By cutting out the middle man you do save considerable amounts of costs,
My current trio of Carvins. Bolt+ C in trans Saphire blue over ash, C66T as described above, and an LB76 6 string bass with 18v active/passive electronics with dual HB's and split switch.
An HF2 "Fatboy" with a Claro Walnut top. I used to own this one, but traded it with a Carvin forum member for the Blue Bolt Plus above. It was a great guitar, and even the thicker neck didn't bother me, but at the end of the day, it and I didn't see eye to eye.
And now for my "modern" X100B; stock outside of the cosmetics. This was the first ever two tone finish on a Carvin halfstck. It's a great "modded Marshall" kind of amp. It has amazing cleans, and the distortion channel can handle blues, to rock, to hard rock, and even metal (although not the Djent thing) without a pedal. The head and cab, with the custom cosmetics was well under a grand.
So with that: Cheap? No; Affordable? Yes