You want it cheap enough to keep your guests happy, but high enough to get you some money. You can now raise the entrance price to the park to around $15-$20. When you do want someone to mow the grass, hire a handyman specifically for that task, and uncheck all but the mow grass option.
You don't need that (mown grass just looks nicer). Uncheck the handyman's option to mow the grass.
Now that you have some rides going, hire one of each type of employee. You want at least one indoor type ride, like the Haunted House. This is how real amusement parks design their parks in case you didn't notice. The rest of your roller coasters you will build deeper into your park (you build only one by the entrance since they will have to travel to the others, and will sometimes see other things on the way). Place one, and only one, rollercoaster by the entrance to get the guests' hearts pounding early. Build a good mix of rides, some gentle, some exciting, and of course a roller coaster. You can now start building amusement rides.
