Alex already covered most of it, but I still have something to add here, which is more like an advice.
You should try the matched box for you amplifier first, to get some impressions. (Most brands have all three common sizes (4x12,2x12 ans 1x12) for their amplifiers available) This way you can either be satisfied (in this case, go get the box) or you can tell what's not right with the sound and you can narrow your search.
You said that a 1x12 is sufficient but I'd recommend you check some 2x12, too. They usually unify the best of both worlds. They generally have a much wider and more open sound than a 1x12 and you have to option to use them in stereo AND they are generally cheaper and lighter than 4x12 cabinets. (ergo: easier to transport!) There are also upright slanted models on the market, which have the benefit that you can hear yourself better in band-context, since like a 4x12 the upper speaker(s) goes in the direction of your ears when you stand in front of it.
Btw. You haven't mentioned for what purpose you need that amplifier, because IT DOES make a difference. My advice is targetet to you in the belief that you'll use it in a band context of some sort. It may be a bit overkill to use (for example) a slanted 2x12 with V30 loaded in your bedroom. When I think about it... It's cool anyway! But there's the budget... and the neighbors!
Take Alex' advice about the impendance very seriously! But other than being more or less efficient, 8ohm and 16ohm setups will sound different, too. 16ohm tend to sound more "vintage" (muddier) and 8ohm more "modern" (tighter), but it's a small difference. (but still, a difference)
In general I'm against brand recommendations, but if you want: I can recommend, since you seem to have a rather tight budget, the house-brand "Harley Benton" of the shop "Thomann" (http://thomann.de/). Yeah, you heard right, a house-brand. But somehow they managed to put cabinets on the market with an insane price-performance-ratio, like a sturdy 2x12 with Celestion Vintage 30 loaded for ~200€. The only down-side: They ship to europe only. (I can't tell where are you from) But you can also try to buy a used cabinet on ebay.
Well, that's as far as my recommendations go. I hope you can use some of it.