I personally like 60# Momoi Diamond mono on that size reel myself, but a lot of guys on here will probally recommend jerry brown hollowcore. I like both and will probally upgrade to the JB once I learn more about splicing and making serves
If you're trying to be cheap, just spool it with some 50lb big game. Or you could put some 80 braid backing and then a topshot of 50lb test. I'm assuming youre trolling dolphin/tuna/billfish.