cuz.. you about to step into the realm of toy collecting (and I don't mean the toys you find in the dept stores).
These are specialty collectibles and they've a huge sucking power on vitamin M.. If you get addicted.. haha then you'll become like me.. a guy's whose hobbies are toy-collecting and now.. photography..
For these toys, you can find most of the shops at China Square Central (a shopping plaza near chinatown). On sundays, there will be a flea market there.
For more info, you can check out these blogs on toys:
there are shops in far east shopping centre that carry these figs in the 4th level.
plaza singapura as well, as suggested. sometimes other toy outpost ... hmmn, outposts also have them, depending on the seller. there's also a shop at raffles place SMRT exchange that sell them.
Calling them 'cartoon figurines' is probably the biggest insult one can make at the Japanese anime industry.
Would be nice if you can use the term 'anime figurines' instead of the 'other' term. Japanese anime and their resulting merchandise are at least 100x better in quality compared to crappy cartoons and their lousy toys.
Anime figure shooting is a high Vit M hobby like what weelong mention. To start off you may want to look for figmas (ard $30~$50) or nendorids (ard $50~$70). They are small enough to tag along when you go out photo shoot. Some of my regular "followers" are Miku, Danboards.
Check out www.toyntoys.com @ China Sq as their price is quite good in SG for pre-orders. Their figma/nendoroids price are quite fair also.