This code
if(Convert.ToBoolean(price_range == "<500"))
will not work. Read this
Convert.ToBoolean Method (String)[
^]
Instead you will need to do something like the following
if (price_range <= 500)
Edit: I just noticed that price_range is a string?? If so what you are trying to do is just weird and I recommend you to rethink your design.
Well I guess you could do something like this
string price_range = "Below Rs.500/-";
string[] priceRange = price_range.Split(new char[] { '.', '/' });
if (Int32.Parse(priceRange[1]) <= 500)
{
}