Personally I would have not gone with a 10-30p, even if your outlet is a 10-30r, unless it's all you ever plan to use. Reason being, 10-30r(female version plug) is basically impossible to find. Purchasing an outlet and box is really your only choice which is bulky, costs more and isn't probably waterproof for outdoor use. Instead I would have suggested a L6-30p or L14-30p, both of which the female variety are easily found and at places like Amazon cost <$10.
In your case, unless you want to cut off your 10-30p end and wire on something like a L6-30p, your only real choice for 120v use is to purchase a 10-30p wall outlet(you may be able to find one with a built in outlet box, usually brown in color and Bakelite plastic) and wire it with a 1' piece of 10-3 wiring to a 5-15p(standard wall plug). Running the 10-30s neutral to the 5-15's ground, and one of the 10-30s hots to the 5-15 hot and the other 10-30's hot to the remaining 5-15's neutral connection. Like I said it won't really be waterproof and the 10-30r isn't really meant for outdoor use, but it would work, albeit it bulky and maybe a bit hokey looking.
https://www.amazon.com/Leviton-Dryer-Outlet-Receptacle-10-30R/dp/B00004YUMW/ref=sr_1_3?ie=UTF8&qid=1500469141&sr=8-3&keywords=10-30r
https://www.amazon.com/Superior-Electric-YGA017F-Electrical-Receptacle/dp/B0095GKC8U/ref=sr_1_1?ie=UTF8&qid=1500469199&sr=8-1&keywords=L6-30r
If you won't want to make one yourself you might try VegasBrad on MNL, he may sell or could custom make such adapters, I believe for ~$30 + shipping, although the price could be higher, I'm just going off memory.
10M cord, whoa thats a long one! explains the slightly higher price for your EVSE, still IMO it can't really be too long, especially if you plan on using your EVSE in a variety of places. I got a 8M and have used every bit of it on a couple occasions, safer to extend the J1772 cable than the input cable.