Available for purchase:
— Many houses in the area are for sale.

synonym: purchasable.

Roget 763: offering, offered etc. v.; in the market, for sale, to let, disengaged, on hire.   

Roget 794: commercial, mercantile, trading; interchangeable, marketable, staple, in the market, for sale.    wholesale, retail.   

Roget 796: under the hammer, on the market, for sale.    salable, marketable, vendible; unsalable etc. unpurchased^†, unbought; on one's hands.