The Breakdown:

• Overall, this project cost to date is $103.30.   That’s less than I would have spent for a single really large framed print.  If I had to, I could have done this for less – especially if I were willing to be more patient.
1. If I had placed my order with just one source and for the cheapest/slowest shipping option possible, I might have saved $5 in shipping. 1  For the extra $5, I’d rather have all the parts arrive this Thursday rather than next Thursday or a month or two when the shields were back in stock.
2. I probably could have used an old power adapter from some other old scrap electronic device, but at $6.95 it just made sense to get a brand new device from Adafruit so I could dedicate the adapter to this project.
3. I could have probably done without the micro servo and saved $6.00 since I’m mainly interested in doing single-line drawings – but this small investment will ensure I can do any kind of drawing I want by enabling pen lifts.
4. I recently pulled two tin can stepper motors from old electronics, which could probably do the job.  However, at $14.00/stepper motor the price just seemed right.  These are pretty big motors that would be able to handle negotiating beaded cords with weights, if I ultimately have to go that route.
5. Since I don’t have tons of parts lying around and I’d like to get started on this project before the weekend, it was worth it to me to pay a little extra.  However, if you just had to do this project for the cheapest possible amount and didn’t care how long it took, you could shop around to place a single order with one distributor, recycle a power adapter, and probably pull a small servo and two steppers out of some dumpster-score/junk heap.
• At just a little over $100, I can use an identical hardware setup to John Abella – which means I can recycle his modifications to the Polargraph code.  Since he was using metal beaded cord and printed gears, he had to modify the code to accommodate these changes.  I’ll have to make some changes too – but it should be much easier to do so since I can compare John’s and Sandy’s code bases.  If the parts ship today, I should be able to get them on or before Friday.  The additional benefit of using the US Postal Service is that they’d deliver on Saturday if it comes to that.
• For a full list of all parts I ordered, check out my post “DrawBot – Parts Ordered!!!“

1. Adafruit was out of their motor shields, so I had to go to a third-party.  Admittedly, a third-party I love using.  Waiting until they were in stock and then placing a single order would probably have saved me $8, but the shield was already discounted $8 through MakerBot anyhow.  I guess that would have been a wash… [↩]