SaberDrive #9 x 3" Tan XL1500 Coated Exterior Star Drive Multi-Purpose Deck Screws 1 LB, Approx. 73 Pieces

Q: Is it better to buy screws on Amazon or Home Depot?

It was better to buy the screws from Amazon over Home Depot because the product was cheaper overall and higher quality on my opinion.

Q: Are these screws strong enough to support steps on a deck, without the need for L-brackets?

depends on how you build the steps. If they are the only support of the step NO they are not strong enough. the screws are not by themselves strong enough.

Q: will this work for mailbox door hinge screws?

These are self tapping screws, no drilling necessary, ment for wood not metal. They are long at 13/4". Measure to see if they are too long. Great screws.