Just bought a scooter but of course...for men...better go with the real bike as this country is a bit "testosterone-like"...meaning that a man must have a big bike. As for women, they should not have a motorbike at all...but I don't care because as a Muzungo I do not fall under the same social code (i like to believe).
Sameer Hussein sells some TVs from 1000$ (all included for scooter) to 2000$ for more powerful bikes. For short term stay, it's the best value for money and relative to Asia...VERY easy driving without much traffic and people are rather good drivers (except for some mototaxi drivers that tend to cut you with some sick pleasure).
Sameer is very nice and young owner who will do all the paper work for you. For the money, you should bring 1000 USD or Euros with you, as withdrawal with VISA card (only solution here, credit cards) is quite costly with 5 to 6 withdrawals.
Hope that helped you.