This paper studies a buyer-seller network where sellers offer sign-up bonuses to buyers on points, a currency whose value depends on the effort that buyers invest to learn how to use it. Buyers choose the optimal level of learning based on the total amount of points that they could potentially obtain. Based on the level of learning, they decide which offers from sellers to accept, with a heterogeneous transaction cost of each offer accepted. Examples include sign-up bonus points for bank credit cards, chain hotels points and chain restaurants points, where the value of the points is subjective to buyers' effort to learn how to use it. We study the case that buyers can be of two types: ``incentive abusers", where they eat the sign-up bonus points without providing any revenue to sellers, or ``regular users”, where they also eat the sign-up bonus points, but they bring a positive revenue return for sellers after the sign-up. The paper explores the existence and the uniqueness of Subgame Perfect Nash Equilibria (SPNE) on sellers' choices of sign-up bonus points offered to buyers. In addition, the paper provides comparative statics on changes of the proportion of incentive abusers in the market, the positive revenue return from regular users, the network connections, and sellers' strategies in the game.