When you pay by credit card, the merchant must pay a percentage of the total sale to the credit card company; with debit the merchant pays a flat fee.
The more people pay by credit card, the more of the merchant's profit goes to the bank - so he eventually will have to raise prices accordingly.
The more people pay by debit, the more the merchant gets to keep that percentage as the legitimate profit to cover overhead and make a living.
So paying by debit benefits the merchant more directly but indirectly benefits the consumer in lower prices to make the same margin.
If you pay off your credit balance in full every month it might be to your benefit to use your credit card, but not if you do not pay it off. This start accumulating interest on top of whatever you paid for the product.
Also be aware that when buying things like electronics with some credit cards, you have immediate insurance on whatever product you buy if it get lost,damaged or stolen on the way home from the store, and with all you have the protection of time to dispute charges.
Iti s iportant to READ your cardolder agreement and be sure you understand there are different types of charges subject to different interest and how your payment is applied.
If you have a cash advance on your card AND an outstanding balance your payment is applied first to interest, then to purchases, and lastly (only once all the charges are paid) applied to the cash advance - which is clocking interest at the the highest rate.
this is the credit card trap. As soon as you take a cash advance , if you do not pay off your entire balance soon you are well on the road to never getting out.