MySQL Rounding ??

This isn't really a Drupal issue as it may be a MySQL issue:

I am adding a record to a MySQL table using the following code:

		db_query(
			"INSERT INTO {sl_guests}(uid, nid, model, s_nid, s_model, qty, phone, altphone, email, txt_msg, signupdate, fee, status)
				VALUES (%d, %d, '%s', %d, '%s', %d, '%s', '%s', '%s', '%s', %d, %d, '%s')",
					$user->uid,
					$thisnode,
					$thismodel,
					$shadow_nid,
					$thismodel."~SE",
					$nonmbrqty,
					$me->profile_phone,
					$me->profile_altphone,
					$user->mail,
					$me->profile_txt_msg,
					time(),
					$node->list_price,
					t('In checkout')
			);

When I insert a value for $node->list_price of $1.50 it gets stored in the database as $1.00. Values in even dollar increments, such as $25.00 are stored correctly. Looks to me like some rounding might be going on, but I can't figure out where. The field type for 'fee' is Decimal 10,2. Any thoughts on what might be going on or how to correct it?