means the right of a purchaser of a housing interest-
| a) | which is subject to the payment of a fixed or determinable sum of money by way of a loan or otherwise, payable in one amount or in instalments, in addition to or in lieu of a levy, and whether or not such a sum of money is in whole or in part refundable to the purchaser or any other person or to the estate of the purchaser or of such other person; and |
| b) | which confers the power to occupy a portion in a housing development scheme for the duration of the lifetime of the purchaser or, subject to section 7, any other person mentioned in the contract in terms of which the housing interest is acquired, but without conferring the power to claim transfer of the ownership of the portion to which the housing interest relates; |