I'm now interested in going and discussing the advantages and disadvantages of DIY bio tech with my friends in biomechanical engineering. Plus, I still have to check out the Maker Space at my university, 3D printing the shit out of my SolidWorks models would be fun.
Meh, I think it's nice trend to see people re-creating the instruments most scientists treat somewhat as black-boxes, but having a thermocycler built with 21st century aesthetics doesn't really enable anything that you couldn't already do with a used $200 machine from ebay. And that's still pretty little.
Between reagents and a good collection of basic instruments, you're still looking at thousands to tens of thousands of dollars for even a minimal lab setup. It's not unfeasible to set up a garage lab, but it's also well outside most teens / early adults' budgets.
Some people have proposed microfluidics as a solution to lowering the cost by shrinking everything down, but that has yet to be proven practical as a general solution for biology. Most attempts to miniaturize existing protocols end up being their full-fledged research projects, and usually when you zoom you from the tiny plastic chip, you see hundred-thousand dollar microscopes / lasers / fluid control systems.
When it comes down to it, most lab instruments rely on pretty simple electronics / mechanics. A plate reader is a laser, a sensor, and a bunch of motors to move things around. A PCR machine is a heat pump, qPCR a heat pump plus laser and sensor. But the actual material selection, design, manufacturing, and quality control end up bumping up the price outside of the amateur's price range.
It really depends on the goals of the lab, I think. I think diy bio labs are first and foremost awesome for education, letting kids learn about biology and teaching them the basics of tinkering with cells / instruments. And if they don't mind not being high-throughput or competing with large labs, it's completely within grasp to study less popular systems (think more obscure microbiology, soil biology, worm biology, etc).
But there's also a movement of people who want to close the gap with academic labs on engineering biology, studying personal genomics, and producing new biologics. And there the limitations come down to quality / diversity of instruments and development of new instruments. No diybio lab is going to have a $500k mass spectrometer, but a basic set of incubators, centrifuges, microscopes, and thermocyclers puts them on the path to iGEM (Check out Counter Culture Labs).
Most projects there are still for toying around, trying to make proof of concepts, and learning the ropes of the wetlab. But with, say, robotics to automate things, cheaper sequences, or better DNA printers, they can start to explore more interesting problems that more traditional labs wouldn't normally approach.
DIY bio's science strengths are in pulling together individuals with hobbyist interests, but more diverse backgrounds. It's rare to find a biologist who knows how to build lab devices, and when you're not having to consider dropping $50k / yr on someone who isn't likely to win you more grants, I think it's easier to focus on tackling the more trickier annoyances holding biology back right now... if that makes sense...