I managed to getting it working with a ublox gps off eBay for under a tenner. Certainly cheaper than the adafruit one and also runs off 3.3v. However word of warning it won't flash or blink till it actually gets a lock this is what was making me think it wasn't working. The first time it can take up to 45 minutes to get a lock. But providing you have clear view of the sky I would say around a few minutes max.
There we go, you have the £30 pi just get a £7 ish i2c lcd screen and less than a tenner gps and you to can have a cheap cacheberry pi too.