RV storage in Las Vegas is always at a premium. Because it can get a little warm in Las Vegas during the summer, most seek "covered" storage. In my searches, I've found that rates for covered storage range from about $180 - $300 per month -- with the lower end for back-in 30'x10' spaces. An RV garage space will run from $350 - $600 per month -- and there's generally a waiting list for those. Over the last 5 years, I've rented both the covered storage, as well as an RV garage space.
In the end, I found what I believe to be the best "value" at
Las Vegas RV Resort, 3890 S. Nellis Blvd, Las Vegas, NV 89121. They have RV storage (mostly large back-in sites along the perimeter of the Park) -
all of which have full hookups - an absolute rarity for storage sites. I don't know if the rates have changed, but I've had our 27FB Airstream there for 2 1/2 years @ $100 + electrical. This is a large, 10-10-10 rated park, with 24 hour coverage at the entrance gate. Check their web site (
www.lasvegasrvresort.com) and look at the resort map (under Amenities) and you will see the storage sites designated in "Yellow". Most of the storage sites are large enough for a trailer or motorhome and a vehicle (side by side).
Good luck on your search...
Cris