Documentation states the following:
tez : an unbounded positive float of Tezzies, written either with a tz suffix (1.00tz, etc.) or as a string with type coercion ("1.00" : tez).
Yet the following example in Liquidity produces an error:
if amount < ("5.00": tez) then Current.failwith "Not enough money, at least 5tz to vote"