Revision 3e66c8f7-e97f-4dda-a4ee-66df07bbb5e3 - Code Golf Stack Exchange

# Pyth, <s>13</s> 12 bytes

 hM_BSvsM.p`M

Outputs in form `[smallest, largest]`. Try it online [here][1], or verify all the test cases at once [here][2].

 hM_BSvsM.p`MQ Implicit: Q=eval(input())
 Trailing Q inferred
 `MQ Stringify all elements of Q
 .p Generate all permutations of the above
 sM Concatenate each permutation
 v Evaluate each as a number
 S Sort them
 _B Pair the sorted list with its reverse
 hM Take the first element of each, implicit print

*Edit: Saved a byte by taking stringification out of the mapping function. Previous version:* ``hM_BSmvs`Md.p``

 [1]: https://pyth.herokuapp.com/?code=hM_BSvsM.p%60M&input=%5B22%2C33%2C44%2C55.55%2C33%5D&debug=0
 [2]: https://pyth.herokuapp.com/?code=hM_BSvsM.p%60M&test_suite=1&test_suite_input=%5B22%2C33%2C44%2C55.55%2C33%5D%0A%5B34%2C900%2C3%2C11%2C9%5D%0A%5B99.93%2C9%2C3%2C39%5D%0A%5B45.45%2C45%2C45%2C45%5D%0A%5B12%2C21%2C34%2C43%2C45.1%5D&debug=0