Internet Speed question

ATM I'm playing on a 7MB DL speed, but I'm trying to cut back on some monthly bills to help pay down my wife's student loans faster. I was wondering what the differences would be between a 768kb, 3MB and the 7MB I currently use are. Anyone care to give me some real advice?

768Kb is the slowest but probably acceptable for most tasks. If you are wondering about this game specifically, well it's playable on dial-up.

I am playing FFXIV using internet connection with max download speed at 100 kbps, no problem.