I've been looking for a pair of reading glasses that is easy to carry with and convenient to use when needed. Believe it or not, such a thing is extremely difficult to find.
Finally the ThinOptics caught my eyes in a RadioShack. I bought one and tried, but sadly too easy to fall off to be practical.
Eventually, I found this Bifocal rimless on ebay for only $7.99 shipped from California and so far solved my problem. I simply put them on whenever I go out.
It is quite thin and light, and frame-less:
The lower portion is for reading and the upper portion (quite large - good) is for pure pass-through:
Very comfortable and convenient, no longer look at people like this:
Progressive could be even better, but no such a thing yet! There are 3-focal ones, say, +1.5/+1.25/+0.75, but nothing like +1.5/+1.25/0, or +1.5/0. Why?
[update] Saw this in a local store for less than $15. It is sunglasses with a shallow tint, perfect for all seasons, indoor and out.
Found more bifocal sunglasses in Rite Aid, they are too dark though, the above SIGHT is more versatile.
This is by far the only pair of bifocal found in local stores, that is not sunglasses: