Posts in Tools under $100
Hoffman Box

That's right, you're looking at a pressure cooker. Apparently, it's also a sophisticated test tool. (Who knew?)

Anurag Khode outlines using a hoffman box for testing mobile devices in his post on Hoffman Box Testing in BREW. While the post does appear to have some copy and paste fork-lifting from the Hoffman Box Wikipedia entry, it also contains an interesting set of test ideas.

Apparently, the main goal of the Hoffman box (or pressure cooker substitute), is to shield mobile devices from their signal in an effort to test signal-fade or signal-loss. For $24.00, the Wearever 8-Quart Stainless Steel Pressure Cooker officially qualifies as a test tool under $100.
Personal Dashboards
In a post on productivity tools, Geekpreneur outlined what might go into a personal dashboard. I've used LifeTick for sometime now and am fairly happy with it. I use it to track some personal items, but also my writing and speaking commitments, large projects at work, and general professional housekeeping (website updates, etc...). It's helped. I drop fewer items, and I feel like I can worry less about forgetting to get something done. That frees me up to focus on the task I'm currently doing.
Stomp is a quick follow up to iShowU. Also provided by shinywhitebox, it recompresses existing videos and allows for filters, cropping, and scaling. Runs about $30 USD (at the time of this posting).