I think that can be handle in followup page.

for example redirect from eguide with http argument:
/modules/pico/index.php?content_id=1&price=$10
and destination page (pico/tinyd or blocks) using PHP-eval little bit.

if (isset($_GET['price'])) {
  echo "Price=".htmlspecialchars($_GET['price']);
} else {
  echo "You are lucky, This event is FREE!";
}
?>

Thank you reservation event ...

Of cause I know you will happy direct support by eguide.
--
Nobuhiro YASUTOMI (MySite Users Webmaster)