Depends on the region and supplier, but generally speaking the price per kW of solar install has been dropping like 20-50% per year.

Let's say you spend $5,000 on 5 kW of panels and your monthly energy bill is ~$200. It'll take 25 months or just over 2 years for the panels to break even.

However, panel substrate materials tend to die after 25 years of service life, so for the remaining 23 years that they exist, they will be making you ~$4,600/year (since you no longer pay for electricity).

The main positive of solar is that the sun will literally outlast human civilization and is about the closest thing to free energy that we have in our fucked up world. No one rushes over with an umbrella in public parks and charges tariffs.

Just food for thought.

I'm an engineer who designs solar array for a living, here's how the math breaks down in fairly typical round numbers.

The all-in cost is around $2-3k per kilowatt (thats equipment, installation, permitting, utility approvals, etc), so a 5kW system (pretty typical residential size) would cost $10-15k. Each kilowatt produces about 1000-1500 kWh every year (depending on your latitude and how much sun your roof gets), so if your electric company charges you $0.10 per kWh, that 5kW system will generate $500-750 worth of energy annually. Without incentives it would pay itself off in 20 or 30 years, but if your state has good solar incentives that can be much shorter, if you pay a lot more for electricity it pays itself off sooner as well.

I paid 53k USD for sixty 405w panels installed.