It depends what you mean by sensible. The going rate for unlimited is �15 per month. But look at Worldonline which offers 50 hours a month anytime for �5.99, 100 hours for �9.99
Don't subscribe to AOL or Freeserve. We have used both and have had connection problems. So we switched to free24/7 which offers a good service and unmetered access for 8.99 a month
Try IINET. They offer ADSL, 24/7 and with 4gig/4gig download [ 4 daytime and 4 nightime [for D/Loading movies while you sleep and not impinging on your daytime allowance. And all for just under $40Aust. per month. I changed from OPTUS who were charging $50 p/mth for one lousy gig. Thery brought in a new system but I told them to take a long run off a short pier.