Yeah, get the M305 first, as it will probably increase in value sooner and faster than a SKS. There is a limited supply of M305's and there have been discussions that Norinco's supply may be coming to an end in the next year or two. How true that is none of us know - but just in case, why wait until prices go up? There is no other semi-auto, in new, unissued condition, with great reliability, and battle proven firearm that you can buy, or ever will be able to buy for the current price of the M305. This is as good as it will ever get for a new semi-auto that use the full power 7.62x51 NATO round. Plus there are ALOT of well designed accesories available for it and great parts availability that will not end in our lifetime.
I think you'll be able to buy an SKS for under $200 for a long time yet. Even if supply dries up, there are so many of them around, prices won't go up much on these. Plus they are not as accurate as an M305, which works in your favour of keeping their price down.
Verdict: Get the M305 now, SKS anytime later. I gaurantee you will be sorry if you don't scoop up a M305 while the getting is good.