Where did you get this idea from?

it works with a hash just like it works with arrays

Anyway I have tried it and it works fine for me.

    [% totalprice = 900 %]
    [% FOREACH x IN shopping %]
        [% modelname = x.key %][% information = x.value %]    
        [% MAKE_NAME = information.MAKE %]
    
    Quantity: [% information.QTY %] x [% information.PRICE %]<br/>

    [% ff = information.PRICE * information.QTY %]
        PRICE = [% ff %]<br/>
    [% totalprice = totalprice + ff %] 
    [% totalprice %]#print out 1000
    <hr/>
    [% END %]
    [% totalprice %]<----- 3 -------->
[download]

It prints out 1000 as the final number not 900