Dealextreme.com offers an open-source 3D printer for 423€ (shipping costs included):

http://dx.com/p/heacent-3dp02-3d-printer-assembly-kit-238922#

Spare parts are also available for purchasing.

The store also offers the printing filament bobbins for 33€ (including shipping costs):

http://dx.com/p/hips-gn-1-75-1-0-3d-printer-dedicated-1-75mm-filament-hips-print-cable-green-300645#

The length of the bobbin is not specified but the weight (1.4kg)

I unknown the quality of these products but certainly it could be an affordable solution pour DIY at home.

Alvaro