It's been a month and half since these were released. I seriously have no idea what to price them at, they're rarely seen anywhere.

Old stuff used in my last suggestion over a month ago

http://www.tf2outpost.com/trade/12677341

http://www.tf2outpost.com/trade/12778033

http://www.tf2outpost.com/trade/12535754

http://www.tf2outpost.com/trade/12809726

All of these sold for 2 keys. They're more than a month old though, so they might not be valid anymore.

http://www.tf2outpost.com/trade/13846372 - Hasn't recieved offers in a day. Only open trade anywhere.

http://www.tf2outpost.com/trade/13864895 - Was selling for a key each, used them in the end according to http://www.tf2outpost.com/trade/13885664

There's so little proof of actual trades, but as Jon said some time ago, community market can be somewhat relevant on items like these.

http://steamcommunity.com/market/listings/440/A%20Random%20Summer%20Cooler%20Key%20Gift

Current median price is $2.18 (~1.1 keys), sellers range between 2.37 and 2.70 (some go for 3+), average ~2.54, normal keys at 2.02, valuating them at ~1.3

But since buyouts don't matter at all, I'll just ignore that,

I know most people don't like suggestions based on common sense (incluiding myself), but the robokey gifts, which work in a very similar vein to these are also priced at a key, besides, the only one recent seller (which didn't end up selling) was willing to sell for key, and these things yield a cooler key (worth a key), the lower range should be justified.