Hi. Personally I'd stick with 15ips unless you have a very good reason. Most albums were recorded, mixed and duplicated on 1/4" 15ips tape until the mid 90s.
There are a number of drawbacks to 30ips, especially if you're on a budget of $300. At only 16 minutes per reel, you'd need four tapes just to mix an album and that is going to cost a little less than your whole budget, just in tape.
Also, 30ips tends to destroy the bass frequencies (anything below about 100Hz will tend to drop away fairly quickly) and it will wear the machine down a lot faster into the bargain.
30ips machines aren't that common, it will limit your choices, mostly to the really big, really heavy decks. I am not aware of any small machines which could do this without having been modded outside of design spec.
Larger stuff like the Studer A807/A810 or Otari MTR-1x would typically be available in two versions, a high speed one (7.5/15/30) and a much more common low-speed version (3.7/7.5/15).
If you're happy with 15ips, the Tascam 32 is a popular machine here, and its bigger brother the BR-20 is also nice. I wish I'd bought one in 2003, but alas, the cost...
Other workhorse machines include the Otari 5050, the Revox B77HS, PR99 and of course the Studer A807, A810 and high-end Otari machines mentioned before.
Another popular deck here is the Tascam 22, which is the 32's smaller brother. It can only take 7" spools however, so you would again need 4 tapes for an album, but it would be four much cheaper tapes ;-)
