Transferware is still being made in China, and most teaware here is still transferware, so that is not really a signifier for age.
It is not too surprising you cannot find others similar to yours. They were very mass produced, so not rare, and are not really collected due to the availability of so many other, more beautiful cups. The ones I have, I bought from $2.00USD to $5.00USD each. I will dig some out and post photos. They are different from yours, but I have seen a lot very similar to yours. I do not really collect them either, so I do not have too many.
They date to around the 1930's. Handled teacups basically did not exist in China until the Republican Period (1911-1949). China really had no contact with the western world before that time. It was not until the fall of the Qing Dynasty that it started to get exposure. It was during this time that handled teacups started to really appear. Ones like yours, were crude copies of the Western style, with a Chinese twist.
There are some exceptions. During the mid-Qing Dynasty there are a few examples of handled-teacups, particularly during the reign of Emperor Qianlong. He received tributes from Western countries and would then have Chinese versions made, but they generally were only found in the palace and their quality was exceptional.