OSRAM 450nm 50-80mw Blue Laser Diodes/Single Mode/PL-450 | eBay
Offer them ~$45. Keep an eye out on these, they go cheaper sometimes.
The issue of it being a 3.8mm diode still comes into play, how readily available are modules in this size?
That brings me to a point I want to make. Bloompyle, while in your mind it sounds simpler to build a simple whitelight beam device and then control the colors with external signals, in reality it will be easier for you to build a true laser projector simply because the instructions, hardware and software are all readily available and easily found. By the time you build a sound card DAC or buy a commercial DAC you'll already be pretty invested, either monetarily or in terms of effort or both. Using a DAC of any sort to control a spirograph or something like that is overkill. A function generator or frequency synthesizer would be better, but you'd likely have to buy or build one of those too if you don't already have one.
I understand, and at the moment, I'm just building a basic RGB "combiner" ? Just something that combines the colors using the lenses from O-Like and can make yellow, cyan, magenta, and white, and will look really cool. In all honesty that is my cool, an awesome laser project that I can look at and say "yeah, that's awesome, and I made that." Know what I mean? I'm not even going to have basic mirrors, just a beam coming straight out and chillin. real basic stuff, well as far as RGB's go, it's all new and complex for me haha
EDIT: I don't want this to sound like I'm disregarding your help or info, I fully understand, and I guarantee you that what you've told me will be fully researched, and there will be plenty late nights reading about this, but at the moment I'm starting small, and with something I understand for the most part. I'm still someone who's NEVER combined beams or lasers, so this is still a whole new thing for me, and I'm still gaining info that will help me understand lasers and RGB units as a whole. I just need a good place to start and I feel comfortable with this being it. Thank you so much, all of you, for the help, I've added this to a bookmark so I have terms to look up, and a little bank of knowledge to start at, and refer to. Thanks a ton yall!