SeedHost.eu are offering 20% off their shared seedboxes until midnight 13 September (09:00 on the 14th AEST). Edit: Valid for new orders only, renewals or upgrades won't accept the coupon (see below). Discount applies to the first month.
I've had a couple of seedboxes with this company before and always found them to be excellent in stability, support, and ease-of-use. Because they're hosted in the Netherlands they can actually guarantee a 10Gbps connection to the Internet. (Kinda makes the NBN look a bit lame, eh?)
If you need to boost your ratio with your favourite torrent site then this is a great way to do it. No lock-in contract, cancel any time and use it 'til the end of the month you've paid for. Pro tip: their €5 seedboxes always sell out quickly and you end up having to wait for one. Spend a little bit extra and spring for the €7 box instead, it's actually worth the small amount more for the extra space and traffic anyway.
I've had a biggish seedbox through these guys for about two years. Top connection and peering (ie, since its leaseweb you actually build ratio unlike with cheapie french boxes), never had any downtime and they always fix up anything I break pretty quickly.
Can't fault them at all