Admission refers to money paid by park guests to either access a park, ride a ride, or both. Players in RollerCoaster Tycoon, Corkscrew Follies/Added Attractions, RollerCoaster Tycoon 3 base game and expansion packs have the freedom of determining whether a park operates as a pay-per-ride park, as a pay-per-entry park, or possibly a hybrid of both. However, in Loopy Landscapes and RollerCoaster Tycoon 2, parks are preset either as pay-per-ride parks or pay-per-entry parks, with no option to change the setting. Pay-per-ride and pay-per-entry parks have different moneymaking tools and should be played with different strategies.
A pay-per-ride park allows guests to enter the park free of charge, but rides within the park carry an admission price that is set by the player, based on the ride's quality, age, and rider feedback. Pay-per-ride parks do not require a constant inflow of new guests, however the guests within the park must have enough cash on hand in order to ride the rides, buy food and drinks, souvenirs, etc. or the guests will become unhappy and leave. This is alleviated in RollerCoaster Tycoon 2 by the introduction of the Cash Machine, where guests can withdraw money, increasing the amount of cash they have on-hand to spend.
This system has a couple key caveats. First is the aforementioned incident where guests run out of money. The second, and often more serious, is the aging of rides in the park. Over time, rides will lose their appeal to riders, and riders will be willing to pay less and less to ride a ride until eventually the ride will no longer turn a profit. The time it takes for this to occur varies depending on the ride, but many flat rides can experience this in just a few years. Over time, the player will be forced to reduce ride admission prices, or guests will complain about a ride's high cost and will not ride it. In these situations, the best remedy is to replace the ride with a new one, though in the case of Roller Coasters, custom-designed rides or large rides, this may not be preferable.
A pay-per-entry park charges each guest upon entry into the park but does not charge guests for rides. Gate admission is determined by a number of factors; generally, the more rides in the park, the more the gate admission should be. The game will more than likely notify the player if guests are being deterred by a high gate admission cost, and will likewise advise the player if guests find the gate price to be very cheap. The main advantage of this setup is that the gate admission cost is less affected by aging rides, meaning that a high admission price can be kept for a long period of time, even if no new rides are being added.
The pay-per-entry system has multiple drawbacks. In order for a park to be profitable, new guests must always enter the park. This can be difficult, especially when a park is fully developed and there is no more room for new rides. A park has a "cap" on the number of guests visiting a park at any one time - advertisements can temporarily raise the cap, and expansion can permanently raise the cap, but when expansion is no longer an option, the profitability of the system is challenged. This can be alleviated by discouraging guests from staying too long - as guests leave, more guests will arrive to "fill the vacancies", thus paying admission to enter the park. This can also be aided by periodically closing the park, forcing most if not all the guests to leave, then reopening.
In addition to the issue of long-term profitability, most pay-per-entry parks are hindered by a default setting of the game – the default amount of cash guests will have when entering a park. If guests do not have the amount required for admission to the park, they will be forced to turn around at the gate. Additionally, even if a guest does have enough money to pay the admission, they may not have enough money to buy anything within the park, thus encouraging their speedy departure from the park once they get hungry or thirsty.
Hybrid parks, or parks that charge a combination of gate admission and ride admission, are only available in the original RollerCoaster Tycoon, Corkscrew Follies/Added Attractions expansion pack and RollerCoaster Tycoon 3. The hybrid model is less simple than the other models, because as guests have already paid some form of gate admission, they are less willing to pay hefty ride admission costs, making the rides less profitable.