Vintage WiFi Station -- $15This is a commercial-grade Nokia 802.11 access point. Yes, 802.11, not that fancy Johnny-come-Lately 802.11b or that bling-bling 802.11g. The original.
It runs at a stately 2 MB/s, with none of this rushing around at manic 11 MB/s speeds or barbaric 54 MB/s speeds. It has a removable Bay Networks BayStack 660 PCMCIA card, which I presume can be replaced with something more modern if you want to spoil the experience. And it is an experience, let me tell you. I've done no fewer than six Debian installations over this wonderful example of Scandinavian craftsmanship.
Lest you think this device is obsolete, I should point out that it works just fine with newer WiFi cards. Also, ask youself this: How fast is your internet connection, really? Is it faster than 2 MB/s? Probably not. Probably, you pay for 768 KB/s downlink, and you actually get 480 KB/s. You aren't fooling anyone with that fancy 54 MB/s 802.11g access point (that only actually runs that fast when you put your laptop directly on top of it, anyway). Your bits aren't moving any faster that your ISP says they will.
It's WiFi from a more civilized age.
Laser Level -- $25Bulldog laser level, complete with tripod, carrying case, and eye-protection. Yours for $25.
Intel Centrino mini-PCI WiFi card -- $30This was the original card that came with my IBM ThinkPad X40. I wanted an Atheros-based card, so I bought one and replaced the Centrino card. It's been sitting in its little anti-static bag since ever since.