I noticed you are in MA. A composite or resin step may or may not hold up to your harsh winters.

Personally I would pour a concrete "step" and cover with flag stone. DIY should be about $100-150. It will give you the the stone look you are looking for plus last years and years. Flagstone has an endless supply of colors available. Most yards have then presorted by color and thickness. You can buy by the pallet of by weight. Since you are laying over concrete you can go pretty thin.

Few pcs of rebar for structure. @ $10
concrete about $5 per 80lb bag.
few bags of mortar $8 per bag
stone footing @ $25
Flagstone @ $50 thats a high est.
Wheel barrow to mix.
some scrap lumber to make a frame.

Easy project that could be completed in a weekend. And would look great.

LOL I just noticed your post said stimulated. Maybe thats whats wrong with your search.

On another thought 1 foot thick. You might want to break that into 2 steps. most steps are 7-8 inch rise. someone not familiar with you 12 inch step might fall. It would be better to have 2, 6 inch steps instead.