One of the daunting things about sign on bonuses is hitting the minimum spend requirement on some of the credit cards. $4,000 in 3 months is a lot of money so here are some of the best ways I have found to hit the minimum.
1) Use the card for everything you are already going to be spending money on. Simple enough step.
2) Prepay for known expenses. Example: I prepaid my car insurance policy to help hit a spend minimum because I knew I would be spending the money in future months anyway.
3) Ask your parents or dependable friends if they have any big expenses. You can then use the card for the purchase and just have them pay you back. We did this with my parents when we took advantage of the awesome offer the Chase Sapphire Preferred has currently. We used the card for an expense my parents were already going to have to pay for and then they just paid us directly!