For what it's worth, this afternoon I've been stropping on a 3-1/2" x 9" piece of veg-tanned 'tooling leather' bought at a hobby/crafts store for maybe a couple bucks. I used a couple of binder clips to hold it onto a 1/4" thick, 9" x 13" 'candle plate' of glass (~$4 - $5), also purchased at the same store. My piece of leather has some DMT 1µ diamond paste applied to it (At maybe $12-$15, this is probably the costliest element, and well worth it). As stitchawl said, when using compounds, the 'strop' itself is just a substrate to hold the compound. Choose the compound wisely, and what's underneath it is almost trivial. Literally, anything relatively smooth and flat will work (wood, cardboard, paper, fabric).
I do have a 4-sided, German-made razor strop 'bat' I purchased years ago, before I knew anything about stropping. It's very nice, and was more likely geared towards stropping straight razors in basic carbon steel (the pre-loaded compounds are not very aggressive on higher-alloy steels). Since I started making my own and choosing my own compounds (green, diamond, aluminum oxide polishing paste), I've never picked up or used that 'good one' since. My others perform much better.
David