How will this impact my credit score?

If you combine them and you have no balance owed, then your score will not change. If they increase your credit limit then with a higher limit and no debt utilization (credit owed) then your score will increase.

You would also be better off if you are locked into a fixed APR as all banks are raising their APR's now days. Just read the fine print, if you miss a payment, pay late, or go over your credit limit, that APR could jump sky high.

Also you need to use them every now and then to provide a payment history which accounts for 35% of your credit score.

Hope this helps answer your question, also check the reference I have provided from FICO and you can learn more about credit and get the correct facts.

If you have a balance that is more than 3500 on a credit card they will only increase your limit by 250-500 if you've made all your payments on time to avoid risk.

No, this will not improve your credit score. It may lower it because it's like you are taking out more credit which creates a higher risk

It is best not to put all of the balances on one card. You NEVER want to spend more than 35% of your available balance if you are trying to get your score up. If you do get an increase just remember keep the balance under the 35% and NEVER pay late. If anything pay the smallest one off. You can keep it and use the 90 day rule. Don't put anything on it that you can't pay off in 90 days. This will help your credit score.

Well I wouldn't advise getting more cards if your in debt then you have to pay that 1 bank and you get another card lending from that bank then its gonna be havoc and you'll eventually lose it all.

and this sounds like a debt question, depends on what you buy with it too like if you take out money from the banks (lending from the lender you have to pay that certain interest back

the only thing thats bad with lending is that the banks interest can go up ...

if my advise wasn't helpful ignore it