The state covenants with the purchasers and all subsequent holders and transferees of lease-purchase arrangements entered into by the local school boards, in consideration of the acceptance of and payment for the lease-purchase arrangements entered into pursuant to [the Education] Technology Equipment Act, that lease-purchase arrangements and the income from the lease-purchase arrangements shall at all times be free from taxation by the state, except for estate or gift taxes and taxes on transfers.
NMS § 6-15A-13