Some turd decided to steal the little rubber cap in my rear bumper that plugs the trailer hitch hole on my '01 Step-side Taco. I figured I could just go to AutoZone or something to get a new plug, but no dice

Anyone know where I can get such a stupid little part or is the stealership the only one who would have it? I hate going to the stealership for such a silly little thing because they'll still charge me a fortune even though the part should cost like 50 cents
The plug looks like this:
I think my truck is actually slower without it