Of the two cars advertised, the first is a very rare Belna Coupe, the only other one I know of is Don Williamson's, (I'm sure Don can confirm) so I don't think it's price is too high. The second is a Belna Cabriolet, again very rare, yes the colour scheme is not period, but again the starting price for negotiation isn't miles off.
The ebay car is a saloon, nowhere near as rare, so should be alot cheaper than either of the other two. To restore it totally would not be economic, but if it could be returned to the road without too much expenditure, leaving it in its original 'as found' condition it could be a viable and interesting proposition.
This is another Augusta project for sale
http://www.europeanclassiccars.co.uk/cars_23.html