Be very careful: I find lots of adapters made for welders or other 240V stuff, so they can run off the dryer outlet. But nothing for a dryer. Although the plugs may LOOK similar, they won't fit unless specifically made for a dryer. They must carry the NEMA designation of 10-30P (3 wire plug) and 14-30R (4 wire receptacle). Or, if that's backwards, 10-30R and 14-30P (4 wire plug, 3 wire receptacle).
I also see lots of "twist-lock" cords that will plug into a dryer outlet: these are 240V extension cords that are plugged together and twisted to lock them in place. A dryer cord does not do that and won't fit even though it looks similar.
Amazon used to carry one, and it still shows up, but has been unavailable for some time now. Problem is that the adapter, when 4 prong (dryer) to 3 (wall outlet), must use the ground as a neutral, and that isn't legal to do which in turn means there can be no UL label. That raises the possibility of liability, which few companies are willing to do. If you go the other way, 4 prong outlet and 3 prong dryer, you now have to connect the neutral to the ground inside the adapter and again, that isn't legal outside of a dryer that is grandfathered under the law. Same thing: no UL label and increased liability.