wad da...
all driving centres will kinda 'rent' their bikes to you to take your tests... it's already inclusive when you book your TP test date with the centre.
and i seriously doubt they allow you to use your own bikes during the tests, well maybe i am too outdated... took my 2B couple of years back...
and btw, can try "bike production" along bendemeer road. their bikes are rather cheap, but the customer service there cannot make it...
for 2nd hand 2B bikes, the instalments are usually less than 200/month, even if you pay over a period of 2 years. hope i did help you abit...