Good question - if budgeting is a factor, probably in the neighborhood of 300-600 dollars at the bare minimum, depending on what's out there. I would take a look at http://www.mikeouds.com/messageboard/ which is a good resource with various folks posting and looking for / buying/ selling ouds, and also even https://larkinthemorning.com/search?type=product&q=oud where there are ouds for about 400 dollars. It's also important to understand that although anything is possible in terms of being lucky in finding a gem for a low price, expectations should be calibrated accordingly. But for a beginner these types of ouds are totally viable. Viken Najarian at oud.net offers new ones which are higher quality and at a higher price, but also occasionally comes across used ouds at lower prices as well.
If anyone has further questions, please let us know and we can help find you an oud! 🙂