(1) You could file a claim to recover the difference between what you were promised and what you were actually paid. Small claims court is a civil proceeding. If you use the word "charges", people will think you're charging the contractor with a crime. Unless the contractor never intended to pay you $25 per hour, he didn't commit a crime, and you shouldn't use the word "charges" to describe what you're filing.
(2) If the contractor promised you additional work and then didn't hire you, you might conceivably be able to recover the difference between your actual earnings and what he promised you. If you decided on your own not to work for him, you wouldn't be able to recover. In any case, you would have the obligation to attempt to find other work in order to mitigate your damages.
(3) There might be some situations in which you could recover from the homeowner, but this is probably not one of them. For example, if the homeowner explicitly agreed to guarantee payment of your wages, (s)he would be jointly liable with the contractor. Similarly if the homeowner and contractor were acting together in a joint enterprise of some kind. Most likely, however, the homeowner contracted solely with the contractor and not with you. Lacking what's called "privity of contract" with the homeowner, you would probably not be able to recover from the homeowner.
(4) Check the Delaware small claims rules about recovering court costs. Generally speaking, small claims courts *do* award a prevailing plaintiff an additional amount equal to the filing fees. Also generally speaking, you can't recover attorney's fees or other costs unless there's a statute that explicitly says you can.
(5) There is a well recognized right to recover damages for the intentional infliction of emotional distress. Your distress would have to be extreme, and you would have to show that the contractor intentionally did things that he knew or should have known would cause that distress. The mere fact that you're outraged over being underpaid would probably not meet the required threshold.
In a case like this, your credibility as a witness is paramount. You say he agreed to pay $25, he'll say that he didn't, or that he agreed to pay "up to" $25 if he could afford it. If you lash out at the homeowner, who's probably an innocent bystander here, or seek to recover for future wages or emotional distress, you will damage your credibility. Furthermore, if your purpose in filing suit is something other than just recovering money (e.g., "proving a point"), you risk a countersuit for abuse of process.
On the other hand, if you go into court and calmly present your claim for the lost wages, you should expect the court to give you what's due under the law. The key thing is to tell the truth, and to appear to be telling the truth.