rm -f files starting with a digit

Something like this should do it:

$ rm [0-9]*

Remember you can always use echo with any globbing arguments prior to letting rm run with them.

$ echo [0-9]*
100 1,208.8 16.7 21.78 2.56 269.96 30 42.81 4.29 5.58 71.24 8 8.36

After running the rm command above:

$ ls
filter.sh  purchases.csv  README.md