>>193
I would give the /ohm/'s pastebin a try for information:
http://pastebin.com/9UgLjyND
I can't really recommend you a kit to buy since I don't have much experience when buying those online, look at the comments before buying.
For the software I can recommend you LTSpice, it's also compatible with eagle if you want to start making your own boards, there are some more programs in the pastebin.
I would recommend you to build a variable PSU, it's a must have device which can take a bite out of your budget if you buy it, but making one by yourself is very easy and you can make it for less than 20$ in the worst case.
Here's the one I made and I'm still using to this day, I might upgrade it in the future, but it has only given me a single problem, despite shorting it out hundreds of times and lots of inductive kickback, and it was as easy to fix as to replace the regulator.
http://www.instructables.com/id/Fully-adjustable-double-output-power-supply/
>>194
http://pastebin.com/REcvbNhy
The program could be written in a much better way, but at least it works and I reduced the refresh rate to 10.2ms, i think the link will expire soon, I'll reupload it if someone is interested.
I guess it is a common anode, since the digit pins must be HIGH while the segment pins (a,b,c,d,e,f,g,.) must be LOW in order to work, just the opposite of this gif.
Protoboards look pretty crappy, but they get the job done. PCBs can be crappy too, I use the toner transfer method and it's hard to get it perfect if the toner level is below 1/2, holes start to appear quickly and you have to make big traces to ensure they won't come out damaged, this one came out a bit crappy. Also, it's not easy to get the transfer right all the times, the board and the paper must be absolutely clean.
However I do like to design circuit in eagle, it's much more satisfying to drill all the holes, insert the components and solder all at once than to insert the components and constantly check for the best arrangement.