How big is your bank?
You should be able to get one from $80 - $500 depending on the size of table you will be playing on.
If you are just looking for a plain jane cue to start, for example Dufferin
http://www.fgbradleys.com/fgb-cart/default.asp
Search for "snooker cue"
Standard length is 58"
Personally, I like:
9 to 10 mm tip
Soft, using Blue Diamond now, have used Elkmaster.
Suggest you order a supply of tips when you order the cue.
16 - 18 oz
I have both maple and ash cues, prefer maple, but not a huge difference between the two types of wood.
Traditionally, Jointed snooker cues are 3/4, (and need a special case) but the cheaper ones may be half joint and therefore will fit a standard pool cue case.
Also, the cheaper cues may have a rubber bumper in the butt instead of threading to accommodate mini butts and extensions
If you are going to play on a 12 ft, you will need extensions.
The link above has the cheapo solutions.
If you go to a UK source you will have more elegant solutions of mini butts, telescopic extensions, and a greater variety of cases .
http://www.abcsnooker.co.uk/
I've purchased from both sources.