Sounds like you used a really bad exchange to purchase your bitcoins and got ripped off... or you are buying in one currency, and Mycelium is displaying in another (I think it defaults to USD).
If it was indeed some sort of "fee" that you got hit with, I doubt they will be BTC transactions fees. These are measured in satoshis/Byte and generally aren't very large. If you look at:
https://bitcoinfees.21.co/ you can get an idea of the BTC transaction fees people are using...
As at 1000 UTC 2017-02-17:
The fastest and cheapest transaction fee is currently 0.0000014 BTC/byte, shown in green at the top.
For the median transaction size of 226 bytes, this results in a fee of 0.0003164 BTC.
0.00031640 BTC is ~$0.33c at current prices.
NOTE: Transaction fees are purely voluntary, you can technically choose whatever you like as a fee, even zero... just don't expect miners to include your transaction if you use a low or no fee.
EDIT:OK, so I just checked out the BUY/SELL option in Mycelium...
![Huh](https://bitcointalk.org/Smileys/default/huh.gif)
Simplex wants USD$1200 to buy 1 BTC... the current going rate is around $1050... that is just a RIDICULOUS markup!!?!
![Shocked](https://bitcointalk.org/Smileys/default/shocked.gif)
Indeed, putting in $50 it tells me I'll get 0.03465495 BTC... which is roughly USD$36. So, it seems you just got ripped off by Simplex. Such a shame they are being promoted by Mycelium.
![Sad](https://bitcointalk.org/Smileys/default/sad.gif)
Caveat Emptor
![Undecided](https://bitcointalk.org/Smileys/default/undecided.gif)