Hi,
I do a bit of online buying (and a recent success of selling )from EBay and several US websites, notably Collectiblecameras and KEH. What really helped was having a VPOST account, this enabled me to buy goods from elsewhere with a US or UK shipping address.
I totally agree if you want to limit your purchase to a certain value, eg. < 50 USD or <100 USD and slowly work upwards. Buying from EBAY isn't necessary cheap, while it is getting safer, it can still be a bit of tee-kum of quality. Of course, there are additional work to be done to make online transactions more secure, eg, having a paypal account, centralising all purchases to one card with a small ceiling llimit etc.
One of the biggest cost factor comes after you receive the goods, eg. the camera and more often the lens may require cleaning, and this costs at $100 for a proper cleaning.
I like to use the fishing analogy when buying RF cameras, be patient until you get the price you want. Impulse is the enemy of the price-conscious. This is my biggest difficulty though I have gotten a good prices for old RFs.
BUT... before you go buying, I strongly suggest that you start reading up on Rangefinders, the history, the type and do various price comparisons. Learning about RF is just as fun.
hope this helps
raytoe