Hell yes. In fact put it on the tax reforms and let us get a tax charity break. This way if you want the wall you can donate. If you don’t want the wall don’t donate. Keep this on the reforms until the wall/fence part is fully funded. Then separate the rest of boarder security out.
Another way to pay for the wall is to have a entry fee at the US - Mexico boarder for freight and car traffic coming into the US. Just a small fee of maybe $5.00. This way Mexico will be paying for the wall. Then stop when the wall is fully funded. It can be like a VAT (Value Added Tax) or you can call it a Wall Added Tax or WAT.