You can't just embed a function call inside a quoted string.
Write it this way:
"...ourprice=$myrow[rd_ourprice]&tourname=" .
urlencode($myrow[TourName]) .
"&depdate=...";
Come to think of it,
tourname = urlencode($myrow[TourName]);
would have worked if you had remembered to include the $ on $tourname so it was an actual variable, i.e.:
$tourname = urlencode($myrow[TourName]);
echo "<a href=\"....&tourname=$tourname&d...";