Before I begin, actually, I'd like to say, in full disclosure that I am not paid by anyone mentioned here, nor have I been given any products. Any products by these people that I own were bought by me. I am speaking from consumer experience only.
1. Let's just start with the Geek Toy mecca: www.thinkgeek.com
They have an abundance of super things to choose from including t-shirts that range from $16 to $19 and cover every bent of geekdom: manga, math and science, computer techie, gamers etc. They also carry one of the most comprehensive inventories of weird and wonderful geek toys and gadgets like plush microbes and tribbles, trebuchets, magnetic cannons, slide rulers, office monkeys, I could go on and on. And right now they have a Holiday Gift Guide so you can choose by price or category.
Everything you see here costs less than $40, most of it ranges at $20.
2. I've never known a geek who didn't have a penchant for soda or USB devices. How about a USB mini fridge? These run in the range of $15 to $30 depending on the brand you buy. Granted some people complain about the cooling power on these. Here's the skinny, they keep an already can cool and are able to cool a room temp can but that takes quite awhile. Let me just say that most of my codemonkey friends were getting their soda from a machine or the office provided cans in a fridge. Keeping it cool at your desk = awesome. Besides who wouldn't want one of these on their desks just to say they have one on their desks?
3. Speaking of soda. Here's one that is so simple that many people don't even think of it. Buy a case of your geek's favorite soda. He or she will love you, I promise.
4. Building your own electronics is pretty damn cool. There are some basic tools you can get for this at very reasonable prices. Take the multimeter - a device for measuring voltage, current and resistance. Just this tool alone will bring hours of enjoyment for the electronically inclined. You can get this in a fairly standard digital version for $15
Or you could go fancy for about $50
Or your best bet: buy them a kit to build one themselves for $20!
Check your local electronics store or online stores like www.sparkfun.com
5. A couple of other great electronics gifts you could get are a solder vacuum ($5), soldering iron ($10), solder lead ($10), soldering iron stand ($6), head lamp ($10 - $20), MAKE magazine subscriptions (1 year print $35, or 1 year digital only $20), or gift cards to online electronics stores so they can build up their parts inventory. Also, a lot of electronic geeks out there are getting into Arduino, check out some fun things using Arduino at www.adafruit.com. You can buy kits, chips, and all sorts of electronic accessories for prices ranging from $5 to $100 or more.
6. Back to the idea of soda. Your geeky friend is probably a munchie junkie on top of loving soda. A gift basket of munchie foods will be applauded. If you're worried about the health of your geeky junkie, fill the basket with healthier options like juice, crackers, popcorn, they'll still love you.
7. Don't forget coffee. All geeks practically live on coffee. In fact, let's just say that the four food groups for most geeks are: soda, chips, coffee and coffee. Don't think you have to go off half-cocked in the wind with your budget on this one either. It doesn't take a giant 220V machine to make a great cup. Bodum's been proving that wrong for years now. As for espresso and latte, try stove-top moka pots ($10 to $40) for the espresso lover, or Mr. Coffee and Capresso both have machines in the $25 to $50 range that get high reviews on Amazon.
8. For geeks that aren't translucent from being inside 24/7, you know the outdoorsy, hiking camping type, here are some great things you can shower them with. A firesteel
costs around $12. A self powered radio with solar power and cell phone charger costs around $35. Or an outdoor kitchen set that includes things like portable cutting board, collapsible spatulas and spoons, small spice jars and s&p shakers can be found for around $40. Or how about a set of two collapsible stainless steel wine glasses for $25 or stainless stemless wine glasses for $20? You could throw in a bottle of wine if you felt inclined to spend a little more.
9. For the girl geek specifically, check out www.etsy.com for great computer parts turned jewelry. You'll find circuit board necklaces, capacitor earrings, and all sorts of geeky fun. Just search computer jewelry, electronics jewelry or circuit jewelry. Prices start as low as $5.
10. Any geek loves his dry erase or chalk board. These can be bought new in many ranges, or what I did was buy a used chalk board and repainted it with chalk board spray paint. If you're handy enough, you could paint some board (chipboard or other appropriate medium), frame it and voila you've made one yourself. Don't forget they need supplies for their boards. So you could buy chalk or dry erase pens for great prices too!
Well, hope this helps. Now go make a geek glow with happiness.