1. capital one has a service where i can transfer my balance from another credit card. if i transfered my balance from another credit card (both visa) does that mean i combine the limit? say i have $500 limit on capital one and $500 on card A, when i transfer my balance from card A to capital one the limit become $1000. am i right?
2. when the balance is transfered, will my card A be automatically canceled? or do i have to call?
i just want 1 card.
3. also can i do that from master card to visa?
how do i combine my credit card limit? so i just have 1 card instead of 2.

No, if you have a $500 limit on one card and transfer $500 from another card you have $0 available credit on the card you transfered the balance to and $500 available on the card you transfered the balance from.

Don't cancel any card. IF you cancel them it worsens your credit record and score.

Beware that you will pay a 3% transfer fee to get the lower rate. Figure that in. Make sure that it get paid off in the 6 months to the year that they give you.