It'd be a lot cheaper to just enforce the fookin' laws. In fact, doesn't matter how expensive a wall is, it'll never work if we let people ignore the law.
I agree with this. There are a few steps you could take where you would no longer NEED a wall. In fact, you wouldn't want one because the illegals would need easy access to self-deport.
1. Shut down access to all government services to illegal aliens. This includes schooling for their children!
2. Make it illegal to rent property to illegals. If you rent to illegals, you are abetting their illegal status in this country. Expand eVerify to potential landlords so they can check up on tenants. Hefty fines apply.
3. Speaking of eVerify, expand it to all potential employers and make it mandatory.
4. Enforce the immigration laws against employers at all levels to the maximum penalty.
5. Require or incentivize local law enforcement to turn illegals over to immigration for immediate deportation. (Or penalize them if they don't.) Seize all assets of illegals caught in the commission of a crime.
6. Remove birth naturalization for illegals. Only the children of those legally in the country receive birth nationalization.
Do these things, and the illegals will self-deport. They'll get out the same way they got in... they'll walk across the border with little or nothing. They'll have no reason to be here - no services, no school for their kids, no job, and no place to live. Without those things, they know they'll be easier to catch, and that local law enforcement will turn them over in a heartbeat or their city loses all federal funding.
Wall? Who needs a stinking wall. We'd need people handing out water to the people walking BACK across the border.