Its normal to get spotting when you are skipping your period for 3months.
Im on yasmin and I initially went on it for my skin, which has worked out fantastic. It is expensive, I pay $55 for 3 months and that's a standard price no matter which chemist you go to. If you are in a private health fund and are using it for your skin, you can get a letter from your doctor to say that's what it is used for, send it to your hf along with receipts and most will rebate up to half the cost.
Apparently there is a new form of yasmin called yaz, which has less of one of the hormones (i think its estrogen though i may be wrong). it gives you the same skin benefits and contraception but is meant to reduce side effects like bloating, withdrawal headaches and i think maybe spotting. Its just come out though and I think it starts at about $80 for 3 months and im not sure if that's rebated.