Absolutly, everybody can go out on big game fishing!! You get a lot of help so it´s no problem!!
Cost, for a full day with a 42 footer about 600 Euro. You can always try to share a boat with somebody. Just call to the different operators and tell them that you are interesting in sharing a boat. Many operators have their own websites
If you dont want to spend upp to 600 E so is there even small game fishing. Smaller boats and smaller costs. Try to ask around when you are on Mauritius, you never know what you find...