The T-70 might be more affordable for the time being. The Black Hawk has much more adoption in the market and with the TSK already operating Black Hawks, the induction training and maintenance cost of the T-70 will be relatively low. The T-625 is a new design that has yet to develop scale to widely distribute the R&D overhead. It could be a decade or so of production before the T-625's unit cost reaches the level of the AW139.
The T-70 could also be more suitable for wartime utility tasks. While the T-625 would make for a great general transport and search and rescue chopper, the T-70 can be adapted for naval AShW/ASW roles, special ops missions, and hot-zone insertion and extraction.
The T-625 is a great project though, but the aim is to give Turkey a marketable product for export, and that too in the long-term. Patience is the key, the best approach is to gradually build scale via domestic orders, and when the price point is low enough, make a heavy drive in the export market.