The cheapest way to go for a knitting machine is to get one of the ones called Fashion knitter. It is a very basic machine that is like the Ultimate Sweater Machine.
I have been reading bunches about the different machines available and besides the bond there is only one that is currently still being made.
You can watch ebay for some machines but a lot of them get to be very expensive to purchase in auctions. Even parts for many of them are expensive.
You know the machines only do a knit stitch unless you hand manipulate the purls or have a ribber (garter carriage will do purls but those were only made for brothers and are very expensive to buy).
I just went through many searches for one of my machines (a Brother KH341) trying to find needles for it. I finally managed to find 25 of them from Needle Tek, but other then that I found nothing.
Since the needles are getting just as hard to find I went and purchased lots of extras for my KH910 and KH930, plus a bunch for my ribber attachment. Then I managed to find a few for my KH210 machine.
If you decide to check out the machines on ebay make sure the parts are all there. You can go to
ftp://ftp.brother.ca/ENGLISH/KNITTINGMACHINE/ to download some free manuals for the brother machines to be able to see what parts should be with the machines and therefore be able to ask questions of the seller.
I am not sure if there are any online sites for some of the other brands of machines that are found at ebay but some searches or asking in groups (there are some nice groups at yahoo), can get you some answers to that.
Do realize that just because you needle knit doesn't make for an instant "I can machine knit". I do needle knit and loom knit, still the learning curve for my machines has been driving me nuts. Lots of dropped stitches, ends messing up and not knitting right has been quite common. Figuring out yarn weights for machines is another big thing. What a manual calls a worsted, doesn't match up to what we know as a needle knitter to be worsted. I have had to swatch, swatch, swatch, to figure out tensions on the machines I have.
You also need to ask yourself just what you want your machine to be able to do, such as yarn weights. I have a 210 that is a bulky machine, it can use thinner yarns but I often have to double or triple them, it does sports and worsted fine, but balks at the chunky yarns. I also have three standard machines, they don't even much like the sports weights of yarns, even at the highest tensions. There are a couple of good articles about how to choose a machine:
http://www.geocities.com/Heartland/Shores/4536/machsel.htmhttp://searchwarp.com/swa230346.htmhttp://www.yarn-store.com/knitting-machines.htmlthat you might want to read over before buying a machine. Then there is this:
http://www.yarn-store.com/knitting-machine-chart.html Which is a listing of many machines giving info on the type of machine, age, number of needles, and other info that is good to know.
I have spent a small fortune just getting my machines into working order. Now I am learning to use them, well I think I am. ROFLOL
MaryJeanne