Yes, you can. This is the cheapest, but most time-consuming way to do it.
You will need to learn how to use several online tools.
To make your ads you will probably need a design tool like Canva.
For imagery you will need a subscription to an image library like Shutterstock.
For the text in the ads, you can use ChatGPT to help you.
Most importantly, you will need to be able to use the AdManager tool for each of the social networks you wish to advertise on. This allows you to upload, publish and track the performance of your ads.
Most small businesses will find this DIY option quite intimidating and a major new workstream in their business.