As johnelvis said, 120 is no problem. The scratch should be no problem but if it bothers you fill it in with some black paint and a fine tipped brush. Light rays bend around either one but the scratch May introduce flare under some(not all) conditions.
$50 is an excellent price if the shutter is consistant. When you check the slow speeds there should be no hesitation just a steady zzzzp.
(hope I spelled that right) :)
Generally issues with leaf shutters are most noticeable at slow speeds, so BobD's suggestion of testing by ear is usually OK. If the Yashica 24 will work with 120 film, it's hard to go too far wrong for $45. As you say, it's a way to test whether you like the format. Definitely look for haze or separation, but don't be too concerned about small scratches or coating marks.
If you were ready to invest $200, I'd say save the $45 and get a good Yashicamat 124 or Rolleicord. But even then, for $200, you're unlikely to get one that's recently serviced.
But be realistic. You're talking about a camera that is probably 40 years old.
I have a Yashica, Minolta Autocord and a Rolleiflex tlr. For starting out, I think you should consider getting a Yashica, unless you can get lucky and get one of the others for a good price. Try to get one of the earlier Yashicas with the Yashinon lens. The later Yashica 124Gs are nice but they are over-priced in my opinion. See if you can get a deal on an early Yashica 124, Yashica D, LM, etc.
Ricoh made some very nice tlrs as well.
If you get a Yashica, consider flocking the film box to reduce flaring. One some models the film box does not absorb light properly leading to annoying flare. Flocking is quite easy to do.
I have a Yashica 24 like johnielvis and also have had no problems in terms of sharpness using 120 in a camera that is supposed to use only 220.
Now if you had of asked for rangefinder advice, most would suggest Leica,an SLR? most would suggest a Nikon and so it goes with TLR most will suggest Rollie.
Look, there are some fantastic photos in the gallery taken with a Seagull TLR. A Magnum prize has even been won with a box brownie.
The vast majority of film cameras are getting old now and ALL need some work at some stage.Grab the offer of the Meopta for the cost of postage and see if works for you.This is a very thoughtful offer.While using it do some research on a short list ,Rollie/yashica/autocord/diacord/meopta/whatever else looks good.Then trust you instinct and buy one.
regards and enjoy
FWIW, my TLR is a Ricoh Diacord that I bought an a photo forum (don't recall which one) for about $50. Some thoughtful soul before me removed the controls for the meter and bolted on a plastic disc to cover the hole--the the selenium cell is still there with its little pop-up cover, which is good for impressing the youngsters. ;) Getting to the point, it serves me perfectly well. I like its character, though I also like a FED-2 with collapsible Industar so take it with a grain of salt.
I took this photo using 120 Delta XP2 in a Yashica 24. I had also just flocked the lens/film box. I can't tell the differences in terms of sharpness comparing shots I took with 220 and 120 film.
WARNING on the Yashica shutter: DO NOT try the self-timer. this is the red-dotted lever at the bottom of the lens. Just avoid it for now. two reasons:
One, the shutter will be seriously jammed if you activate the self-timer when the flash sync (middle right yellow dot lever) is set to M. There is a physical mechanism designed to prevent you from doing this, but it doesn't take much to over-ride it. Again, DO NOT USE the self-timer if flash is set to M.
And knocking that little lever to M is not difficult!
Two, the self-timer is often dirty and dragging. Although you can often just push the lever until it winds down and releases finally if it does drag, just don't chance it for now.
Freestyle sells 220 film, but keep in mind the extra hassle of developing it yourself -- special reels and so on -- commercial? Just make sure they know what you are giving them.
As to which camera -- for all TLRs check for shutter operation -- slow speeds should sound smooth and snappy, self timer should not drag (although nobody ever uses them so this is not critical except a draggy self timer shows that other parts of the shutter are also needing service). Check that wind mechanism is smooth and sure---make sure, as you focus, that the lens panel all rises away from the body of the camera evenly, that it is not out of alignment. Dents and dings are a huge red flag.
Rollei or Yashica? You save a bit buying a Yashica, and the lenses on the newer ones especially are very good, but the extra you pay for a Rollei pays dividends, although service also costs more. Compur shutters tend to not age as well as the Seiko ones on the Yashicas if ur looking for an older camera that can get by without being serviced right aweawy, but when a Compur shutter has been serviced it is heaven.
All these cameras are 30-50 years old, so you pretty much better plan on having it serviced if not already. Essex in New Jersey is good.