Not ready for prime time
You made the simple sculpt; you’re ready to cast, but, the budget says no. There is an option: resin cast.
The resin cast is less expensive because there is not any wax work, no investment shell to make, no bronze metal is needed, the chasing of resin is simpler, the final finish can be as simple as paint.
If you were planning on multiple copies you would have needed the mold. If you had sculpted in wax you wouldn’t need the mold. Cost: often on small pieces the mold for work is about the same as the metal work. It is a chance to see what the final piece will look like.
EZ-On has a plethora of how to videos to walk you through a simple mold making expercise. You can pour your of plastic resin, now you have a casting. Most foundries are more than capable of resin casting.
Like the results, ready for bronze, you have a reason to call the foundry. Want to save a bit more? Pour your own wax in the mold then clean it up to the point of gating ready. Talk to the foundry. Not all waxes are created equal. The waxes are meant to be burnt out in the investment process, thus, some waxes are better than others.
Realize there may be some trepidation by the foundry when you ask them to cast from a mold they didn’t make, or a wax they didn’t make, but with an expectation by the customer it will be perfect. Talk to the foundry and get them involved early. The foundry’s expertise can be invaluable.