Programming :: The 'a' String Doesn't Have Any Spaces In It?

I have a file of the type:

a = b

where a is any string and b is an integer The 'a' string doesn't have any spaces in it.

Everything was running fine till I was searching for 'a' and finding value 'b' by expression

Code:
string="$a"
egrep -i -m1 "^[[:space:]]$string[[:space:]]*=" | awk -F'=' 'gsub(/^[[:space:]]+/,"",$2)gsub(/[[:space:]]+$/,"",$2){print $2}'

I recently ran into a situation where in the string 'a' had symbols like $, & in it. Though I haven't checked it for & but $ is definitely breaking my code

Any way to egrep for string with $ ??

One way I though was to replace every occurence of $ with $ in my search expression but that would involve an extra processing each time