This one looks pretty good for the price, if you buy it from a 3rd party seller you can save an extra $200 or so, they seem good enough but it's up to you.
If you plan on buying soon, I would also look at
this one which is on sale - a slightly better machine, but it maxes out your budget before taxes/shipping (Also a 3rd party seller).
If neither of those fit your tastes - some advice that I would give to help you search on your own:
You want a mesh front panel, not a solid plastic or glass one.
Make sure it has an SSD and not a HDD, both is okay but you want at least one SSD.
Stay away from SFF (Small Form Factor) machines, they're expensive and can be a hassle if you don't know what you're doing/how to maintain them.
2 sticks of ram 2x8 is better than 1 stick, always lean for more sticks when possible.
Finally, depending on how tech savvy your husband is - you might consider getting him the parts to build his own PC, this is usually a better deal than buying one - but you are ultimately your own tech support if you do so.
Newegg is my preferred retailer, hopefully if neither of these machines look good to you you can use them to find the machine you do want with the advice above.
Last notes:
You'll need peripherals, something to keep in mind - I'm sure you have a mouse and keyboard laying around somewhere. And a TV makes a great monitor in the meantime.