There’s a lot of variation depending on the exact location, size, and length of your advertising. Typically, you’ll have to spend around $1800 for 1 month of advertising, but the rate can be much higher in more highly congested areas.
On top of that, remember to factor in billboard design and printing costs. Billboard design typically costs around $200-500 for a concept & multiple rounds of edits. Since you already have a design in mind, you might be able to hire someone for a little less, or even design it yourself if you’re savvy with graphics editing programs.
Printing a full-sized billboard costs around ~$300. Of course, you’ll get around this if you’re running a digital ad!