A very small percent of people will actually comment or like videos.
Check a few videos randomly.... video quality could be better but it's not bad, audio quality seems ok. Lots of uhmmm, ohh, in one video i jumped at some point and right away i got "oh shit, i guess that's why it said that here" or something like that. If you don't seem to know what you're doing, nobody's going to care to keep watching. You can fake it until you get more experience and start to understand some things... editing helps for this. Use the edit functions of a video editor, cut away those breaks (uh, oh, hmmm etc), pause recording and look over something you see in a product teardown, type some chip names in google to get a clue about their purpose instead of just saying something stupid.
Don't be afraid to say "I don't know" what this does, instead of just guessing... it looks worse when you have to correct yourself later in the videos.
Pay attention to the focus and zoom in, zoom out when needed.. for example in the nettest cma 4000 teardown (part2) you have 35 minutes of boringness because you couldn't be bothered to zoom in where needed and show some closeups, or the lightning is bad when you do closeups and you don't explain what people are looking at - the video could have been a 20 minute or less video, with more quality.
And honestly, I wouldn't subscribe because I don't want to see in "My subscriptions" videos about call of duty or other crap - specialize the channel into something - you can make lots of channels and upload into each channel separately :
https://www.youtube.com/channel_switcher?next=%2FAudio can be improved with a good lavalier microphone .. i ordered a Sony ECM-CS3 lavalier microphone for 30$ incl. shipping from South Korea (eBay) because they're about 50$ in ships here... in US they're as low as 16$, here's Amazon link:
http://www.amazon.com/Sony-ECMCS3-Omnidirectional-Stereo-Microphone/dp/B0058MJX4OIn one video you mention that Youtube screwed the audio... stick to ac3/aac stereo 192kbps or 5.1 448 kbps and you should be fine.
Video can be improved with some good lightning.. if you don't mind the heat they generate, these things work quite well and bulbs are cheap (you can probably find them cheaper in home depot or diy type stores) :
http://www.amazon.com/Portable-Halogen-Garden-Weatherproof-Light/dp/B00ET9WT8Y/ref=sr_1_8?ie=UTF8&qid=1397939710&sr=8-8&keywords=500w+halogen+garden+lamp There's also lamps like these... brand sounds like Chinese crap but they do work quite well for the money (search for the product code on amazon.com and you'll find them) :
http://www.amazon.co.uk/Dimmable-Digital-Camcorder-Panasonic-Samsung/dp/B004TJ6JH6/ref=sr_1_2?ie=UTF8&qid=1397939682&sr=8-2&keywords=led+lamp+cameraGet some A1-A2 sheets of white paper, put them on your desk.. the paper will reflect the light and make your camera work better and so on.... and videos will look more professional with a clean desk.
No need to spend hundreds of dollars to improve quality, with under 100$ you can really improve the quality of your videos a lot.
Someone mentions networking... I don't know.. I hate facebook and twitter, i don't use them. It wouldn't hurt to mention from time to time on some forums you use (like this one) that you uploaded a video and ask for feedback and so on.. as long as you don't spam, you'll be fine. People will start subscribing when they see you have good content.
Funny you have money for an iphone but you don't have money for a pc.... an AMD FX-6300 is 120$, a motherboard for it could be as low as 50$, some ddr3 is 20$ .. with under 200$ you can have a solid pc.
You can buy good used HD cameras from eBay for under 200$, you just have to be patient and wait for good models that show up from time to time. There's even some refurbished cameras on Canon's own online store, with warranty and all that... if you check from time to time there's some very good deals on those cameras:
http://shop.usa.canon.com/shop/en/catalog/camcorders/refurbished-consumer-camcorders