Dedireturn seems to be a good seedbox package with their basic series starting from 19.99$
Cost per GBt is around 0.04$ which is pretty low, the space is ample for 5Tb uploads and the servers are in France.
The FTP speeds are good and it has one of the fastest support .The speeds are consistent and  havent have had no downtime so far
dedisreturn seedbox review
M-Wing
1 Month Price – $19.99 USD
Celeron/Atom 1.2-1.8Ghz+
2GB
500GB
100MBIT
5TB(10mbit after)
A-Wing
1 Month Price – $31.99 USD
Atom 230/D425
2GB
1TB
100MBIT
5TB(10mbit after)
C-Wing
1 Month Price – $38.99 USD
Atom 330/N2800
4GB
2x500GB
100MBIT
5TB(10mbit after)
D-Wing
1 Month Price – $49.99 USD
i3 2130 2×3.4GHz
8GB
2x1TB
100MBIT
5TB(10mbit after)
X-Wing
1 Month Price – $69.99 USD
Intel i3 2130 2×3.4GHz
16GB
2x1TB
100MBIT
5TB(10mbit after)