The Start
So I bought a HICTOP Prusa i3 off of amazon for $360 USD shipped to my door.
Being a cheap prusa i3 I figured it would need some upgrades but I wanted to put it through its paces out of the box without alteration and see what I could get and what benefits I got for each upgrade or attempted upgrade.
Assembly wasn't difficult and only took about 6 hours to do, while recording and taking notes for a voice over. If I had to do it again it would probably only take about 3 hours to do.
First things first, this thing is a beast printing PLA, I was able to get it down to printing 50 micron layers with good quality on the aluminum bed, and if you are looking to just print PLA this thing is good to go out of the box, but you could make some minor improvements in that case. Printing ABS beyond 1 CM in height was a pretty bad failure.
Upgrades
The following upgrades are listed in order of perceived benefit.
Power Supply ($45)
So the power supply that this thing came with worked but frankly its junk, it couldn't warm the hot bed up to 110c for ABS, but even with just this upgrade alone that still isn't really possible. The biggest problem though was once either of the heating elements would engage the PSU would drop from 13v to 10v and a 3v drop is fucking terrible.
I replaced that with a meanwell PSU but you could probably get away with a lower quality PSU that could supply more amperage, I want to be able to run this thing unattended for 24+ hours so I would like something that is less likely to catch on fire and burn down my garage.
Here is a link to the one I purchased, http://amzn.to/1p9lzPo
Cork Insulation ($1)
I picked up a 1/4 inch 12x12 inch piece of cork from a local craft store. I cut it down to fit in between the carriage and the hotbed and cut a channel for the y end stop underneath. Now with this upgrade and the better PSU I can heat up to 111 degree c and hold about 108 degrees during operation. Printing small ABS parts has been successfull.
Borosilicate Glass ($25-$50)
The next upgrade was a borosilicate glass plate. I started with a 200x300mm plate and attempted to cut it down to size. That failed horribly and cost me about 30 dollars. I ended up ordering a glass plate for an Afinia H800 through home depot. That cost me 50 dollars but it was perfectly sized to the print bed, it also comes with binder clips.
I noticed at higher tempatures the aluminum was warping slightly and I only had about a 1 thousandth of an inch gap between the bed and the aluminum. When cold it be fine but after getting over about 80c it would warp and drag, the glass doesnt do that. It also provided a better print surface so well worth it.
http://store.afinia.com/Afinia-H800-3D-Printer_p_60.html
You could definately get away with just using the 200x300mm borosilicate plates that are easily available but then you have to use extra large binder clips to hold it down and I ran into problems with the head crashing into those during the auto home process.
I would recommend spending the extra and just getting the H800 glass plate, but on a budget the standard sized ones work fine.
OctoPrint
Octo print is an amazing open source project for allowing you to remotely print, control, and monitor your printer. This one I am recommending but not assigning a dollar value to because you can choose to run this on an old computer or a raspberry pi. I chose to go with a raspberry pi and epoxy that to the side of the frame. The newly released raspberry pi 3 has been reported to work with this exceedingly well and I intend on replacing the B+ on the side with a raspberry pi 3.
If you go the raspberry pi route expect to spend about 100 dollars on the Pi, Enclosure, Power supply, mem card and webcam/picam.
Power Cable($3-$15)
It came with a cheap short 2 wire power cable going to the supply cutting an old computer power cable or extension cable that has a neutral line is a nice cheap upgrade.
Conclusion
So for about $450 you can have one hell of a 3d printer if you are willing to tinker and assemble it yourself, I am currently working on building an enclosure for it to help with ABS print warping. With the aforementioned upgrades it can print the ABS but air currents can cause it to warp if the environmental temperatures are to low, that will stop that problem.