Out of curiosity, was the seller in the US? It is my understanding that it's not legal in the US for reproductions to be sold unless they are clearly marked as such.
No real value, perhaps a few dollars as a novelty. In the 1960s and 1970s it was very common to encase regular circulation coins (sometimes silver or gold plated) in plastic for use as novelty keychains, penholders, paperweights, and the like.
Nice to see this one again!* :-)
With Hsien Feng (Xiangfeng in pinyin) cash coins, it's often much easier to find a multiple cash in good shape than a 1 cash in good shape - the majority of the 1 cash are quite poor in weight and quality.
*I had several duplicates of these about 10-15 years ago that I sold on the BST forums here any years ago.
Frankly I'm concerned that they all look the same - the vast majority of originals were lost in the 30s when China demonetized, and many more in the late 70s during the run up in silver price - almost all of the ones seen today are reproductions made in varying grades of alloy as well as the odd older fake.
Two pieces that I purchased from a collector of East Asian artifacts who got them in the mid-80s, and whose collection of knives and swords was unquestionable genuine, turned out to be fakes - both turned out to be mostly lead.
Gordian III would be the grandson and son thereof of the former two, if I remember correctly. Silver coins from his reign are quite common.
For " Aurelius" it sounds like you might have Aurelian, who was around the 270s-280s or so (going off memory).