grep is interpolating variable value

Hi

I have to search in a file all lines containing a variable value at the beginning immeditaley followed by '^'. The value of variable can change dynamically. So if the vraiable $a value is something like "blabla" the following works properly.
But if the variable value contains a dollar symobol or '@' symbol it does not work. How to avoid this. I am trying to do it in k shell script

$a = "$FT68WWWJE@DSF";
grep "^$a\^" inpfile > outfile

If escapingthe $ and @ is the only solution, thenhow can it be done?

Thanks

1) you dont say what tool you are using (i suppose perl)
2) read carefully your regexp
if FTblahblah is empy, you are grepping for '^^' in file
that make less sence

Here are more details:
1) yes, i am using perl tool

2)

#! /opt/perl5/bin/perl
my $a="TCFGHLK";
eval `grep "^$a\^" inpfil.dat > outfil.dat`;

When I check the outfil.dat after executing the above perl prg, it contains all rows which begins with 'TCFGHLK^" as expected

#! /opt/perl5/bin/perl
my $a="$ABC1521";
eval `grep "^$a\^" inpfil.dat > outfil.dat`;

In this case outfil.dat does not contain any rows because unix first interpolates $a and finds $ABC1521 and it will try to interpolate it again. It does not find any variable decalred with "ABC1521" name. So does not get any records.
I want it to search for all rows containing $ABC1521^ in the beginnning. Sometime I might have '@' symbol also in the beginning of string contained in $a.
Any solutions

Dont worry about $a being blank. Only worry is when $a contains '$' or '@' symbols

Any help

you are stting $a to $ABC1521
perl interpretes it to a variablename $ABC1521
if you want $ABC1521 mask the $ sign.

it make for me not really sence to use grep in perl.