Firewire cards are very cheap and whatever prices I could give ypu would only be local prices, just do a search relevant to where you are.
Coonecting to your TV means you need some way of doing digital to analogue conversion. Most DV or Digital8 cameras can do this for you. Alternatively there are a number of boxes such as ADVC-100 and ADVC-300 from Canopus. If you plan on capturing from analogue sources such as VHS or BetacamSP I'd recommend the later.
DO NOT BUY ANYTHING PINNACLE!!! Hear me, or should I speak up? Get the ADVC-100 if you want a reasonable priced analog to digital converter. If you can swing an educational discount it will be aroud 200 dollars U.S. otherwise it will be about 250. Well worth the money.