Thanks all of you very much.
GNUtransfer don't offer small packages like the one I need, but they replied
that they only use free software and own private software so I recommend
checking with them for somebody also looking for a VPS provider. Byte mark is
prohibitively expensive for me and even though they seem aware and concerned
about the problem of proprietary software, they don't take it very seriously.
Linode replied that they financially support the software freedom day, but
they don't have a policy on using only free software. I'm still trying to
reach an agreement with Corehost through negotiation. I'm still looking for
more VPS providers that abide by the free software philosophy and therefore
suggestions will be very much appreciated.