You can use these documents to print any character using the character code tables to find the table and the character position: http://www.kioskproapp.com/api/StarPrinter/star-character-code-table.pdf
For example, the £ symbol would be on page 3, position 9C. You can then change the code page using the command ESC GS t n
. where n is the page number.
"\x1b\x1d\x74\x03"
Find more info on this command at http://www.starmicronics.com/support/mannualfolder/starprnt_cm_en.pdf page 2-4.
Then you can simple print the £ sign by printing 9c
"\x9c"
Remember to change back to code page 0, or you might see some odd characters:
"\x1b\x1d\x74\x00"
If you can't find the character in any of the tables then you can save your own to memory. Check out this post for more info about that: Star micronics mpop iOS SDK - Save and print a character using the blank code page