Lens choice for Sony Nex

I have a Sony Nex 5 and I recently my 18-55 in order to buy something else.

I had thought about the 50mm f/1,8 but its low (inexistent) availability here in Italy made me desist.

Then, I found out about the Sigma 30mm f/2,8 but again it's difficult to find here.

Last week I found, for the same price of the Sigma (maybe a bit less) an offer for a used 16mm f/2,8 + M42 adapter + INDUSTAR 61L/Z f/2,8/50mm.

What would you do in my place, wait to find a the 30mm or pick up these two lenses and adapter?

Thanks for you advices, cheers from Italy!