In Raintree Homes, Inc. v. Village of Long Grove, 209 Ill. 2d 248, 807 N.E.2d 439, 282 Ill. Dec. 815 (2004) the supreme court considered whether building permit applicants had standing to challenge the imposition of impact fees, which were required to be paid by each building permit applicant. Raintree Homes, Inc., 209 Ill. 2d at 251-52, 807 N.E.2d at 441-42. The supreme court ruled that the plaintiffs did not have standing to challenge the fees because the landowners, not the plaintiffs/building permit applicants, had actually paid those fees. Raintree Homes, Inc., 209 Ill. 2d at 262, 807 N.E.2d at 447-48. There are significant differences between the facts of the Raintree Homes, Inc. case and ours. There, the plaintiffs had no interest in the controversy because it was undisputed that they had not paid the challenged fees. Raintree Homes, Inc., 209 Ill. 2d at 261-62, 807 N.E.2d at 447-48. The most important difference, however, is that the nature of impact fees is different from the nature of retail sales taxes. In Raintree Homes, Inc., the supreme court noted that impact fees are not taxes, although there are similarities. Raintree Homes, Inc., 209 Ill. 2d at 259, 807 N.E.2d at 446. Taxes imposed under the Retailers' Occupation Tax Act are not taxes upon the privilege of buying, or upon individual sales, but upon the occupation of retailer. See Central Television Service, Inc. v. Isaacs, 27 Ill. 2d 420, 426-27, 189 N.E.2d 333, 336 (1963) (and cases cited therein). Likewise, taxes imposed under the School Facility Tax Law are also specifically imposed "upon all persons engaged in the business of selling tangible personal property." 55 ILCS 5/5-1006.7(a) (West Supp. 2007).