Tigol,
Can you make your way to something like this?
https://www.sweetwater.com/store/detail/ORI5Cd--marshall-origin-ori5c-5-watt-1x8-inch-tube-combo-amp
Sweetwater has a demo available for $400.
I think the smart play is a Katana, but I don't know how your husband feels about solid state. I imagine it won't excite him like playing through a tube amp as God intended. If he's big on Slash, having an amp with a Marshall logo on it might also give him the warm and fuzzies when he's trying for the umpteenth time to nail Sweet Child O Mine (I kid because I care). Any excuse to keep practicing and playing is a worthy excuse. (Side note: The Katana will wipe the floor with an Origin, and all the other amps here suggested, in everything but cool factor. But if he's a straight male he'll probably flip out opening a Marshall box. You will be a hero with the Origin and he'll get a great amp.)
That used Les Paul Studio you linked would be perfect, imo, apart from the paint job. An Epiphone in a burst would be my second choice. But with that budget, you should be able to steal a Gibson.
EDIT: How did I miss the Edwards Les Paul Superhero posted! Mmmm tasty. All you would need is a comically large tophat.
ANOTHER EDIT: Dur, you already have the amp covered. Congrats. It might help if I read the WHOLE thread before I jump in, guns blazing. But is that how you're supposed to internet? I think not.