It's not only Sri Petaling.
A lot of property in the Klang Valley are in steady raise.

Usually when the economics are steady; the property market blossoms as more ppl can afford because of stable economy.

But comes economics downturn; then you'll see drastic drops in everything, property market inclusive!

haha.......I consider that cheap already in Klang Valley.
But anyway, lack of details like you've mentioned to actually evaluate that hypothesis on cheap/expensive.

Best if we knew where exact in Sri Petaling, built ups, type of houses (Semi-d or link or bungalow). How old and amenities in surrounding area.