This was an old post of mine ... but for the benefit of others finding this thread now what I ended up doing was asking my animator to buy his own copy of Spine which he did. This is a reasonable thing to do for a few reasons:
1) Spine is very reasonably priced
2) Your animator will now have this program in their toolbox and can easily take on future Spine animation jobs/contracts from others (which mine in fact did)
3) Your animator is getting back money/equity/love/fame/credit, it's not unreasonable to ask them to help contribute to the startup costs
4) This helps Esoteric Software to continue to build and support this incredible software