Hmmm.... sounds like a Top Gear segment.

Maybe I don't understand the rules correctly, but the SG3 you linked to is an open auction, and the £5 is an opening bid. It's possible (okay, unlikely given how it looks) that there might be a few bids placed on it that would put you over the budget you've set. And considering you've included cab fare as part of the cost, since I drive should I be calculating the cost of gas used to pick up the typewriter?

Buying something on eBay would be tough for me as your very low budget price of $37 CAD (£20) would mostly be consumed by shipping. My only hope would be to buy a machine being sold within Canada, but at the moment there isn't a machine with a starting bid of less than $50, so eBay is out.

My only other options are to rely on a market find, or find something in the local listings.  Looking through the listings there were many typewriters, but I'd have to go with an Olivetti Linea 88 being sold for $30, which leaves $7 for gas, more than enough given it's only a 25 minute drive. There are lots of machines in the $20-$30 range, but most are run-of-the-mill, but with this standard made at the Underwood factory in Toronto, I would have an excellent typewriter that has intriguing styling. 

[img]http://i.ebayimg.com/00/s/ODAwWDYwMA==/z/REcAAOSwAoRXFj9y/$_27.JPG[/img] 

I guess I'd have to do this SG for $20:  http://youngstown.craigslist.org/for/5567221903.html
I could probably get there on $10.00 gas. Maybe not back though; but the rules just specified getting there.
 

Got one!!!  How about this nice 1955 Underwood SX-150 for $20.00.  All I would have to do is to make sure that my car is full of gas (I do that anyway around the first of each week), go from my town of Waco south to Austin and pick it up.  I'll bet I could shine 'er up and git 'er goin' in no time flat.  I've certainly seen worse--like one I picked up a while back that looks just like it. It would be a wonderful typewriter for  me to start out with!!  I've always loved Underwoods.  http://austin.craigslist.org/atq/5560792918.html

Interesting! Seems to be standards all round, so far. SoucekFan, your logic and your typewriter are both a little bit Orwellian - I love that sticker. 

Repartee, I set the price bar low on purpose, because you'd think you can't get anything. I found three typewriters on UK eBay, out of about I don't know, 300 ending within 24 hours. I was amazed, frankly. Shows that it CAN, even now, be done. I found an SM3, the SG3, and a really quite cute, white Imperial portable from the late 60s. Limiting it to the next 23 hours also weeds out anything with enough overt attraction to have had its bids go over the limit before its end date.

You live in Brooklyn, right? I imagine NYC is the same as London, everyone's determined to get money...

Since my 24hrs have not expired, I have changed my mind. I would go for this KMM for $25 dollars. My main typewriter is a KMM, so if I was typewriterless, and could only have one, and had to get it now for sub $30, I would likely go for this:
http://akroncanton.craigslist.org/atq/5572410428.html