Interestingly, I read a blog post where someone was using "fulfilled by amazon" as off-site storage, but I think it was a pseudo thought experiment more than an actual storage solution, similar to those folks who use data-as-video on YouTube as infinite backup storage
Sounds expensive.
You can rent skis for a season for $400, I suspect most rental places are than $100/month.
But skis especially can usually fit in the back of a closet or under a bed.
Kayak? Get a season pass for the rental place.
And the kinds of people who live in places where they don't have room to store a surfboard year-round, are the kinds of people who don't have a bunch of wall space for one either.
I think you might not be totally understanding the concept of small urban apartments. Putting skis in the closet or under the bed year-round doesn't work, because your closet and underneath the bed are already full. (And it's not just skis, obviously -- it's boots and poles and helmet and bulky jacket and snowpants and gloves and everything.)
Because yes, you have to pay sales tax on eBay, even for used items that already had sales tax paid on their original retail purchase.
On ebay? Sell the stuff now, buy it again if you need it. Doesn't work for everything, of course, and I don't practice it, I've got tons of space and tons of clutter.