The cost differs extensively depending on the brands of the components you select. There are premium brands out in the market, and there are also economically affordable brands.
However, it is always best to seek advice from an irrigation specialist and let them give you some options to choose from.
The sole purpose of having the irrigation system is to be hands-free for your landscape. You should not assume that buying a premium brand will give you a longer-lasting irrigation system.
You may spend $500 for a simple tap timer controller, backflow to stop water from getting back to the water source, driplines, and drip-line accessories. You may spend $5,000 to have the irrigation system for a broader landscape.
It all depends on the size of the landscape, your budget and as well as how experienced your irrigation specialist is. Designing an irrigation system is very flexible, allowing you to select the components used based on your budget.