With more and more purchases being made online you really need to have a credit card to pay for them.  If you want to send a personal check the time you have to wait for your purchase is quite a while, the check has to clear the bank and then the product will be shipped.  That is if they will even accept a check or money order.  Some won't.

If you do have a credit card it might be wise to research to see who is offering to accept a transfer of other balances (from other cards) for zero cost with a lower interest rate.  There are sites 0% credit cards  that will help you with the research and you can see whether it would be a benefit to you to transfer.