If you want something that does it all for your price, get a Miniak ( but remember no USB)
if you want something portable and dont care about smaller keys get a MicroKorg)
both choices are a bit of everything, but if you have things to already do leads and pads and just need bass. >>
if you want a fat bass analog bass sound get a monotribe, then save up for something else with your change.
If it is for professional music recording, wait and get a Minibrute, but remember it will be monophonic and no presets.
if you are not actually sure what you want, spend £25 on apps, rinse them out and then go and play around in a music shop. This will tell you all you need to know about what feels good and what just doesn't appeal.