First, make sure that "service" or "gratuity" has not already been included. Some luxury places in the US include all service fees to relieve guests of the burden of tipping.

Unfortunately,

1. Conventionally you need to tip the valet $2 when you pick up your car, regardless of the price of valet parking.

2. The "double tax" rule is out of vogue because tax rates vary a great deal by locality. Tip 15-20% of your bill.

Now, the $150 price may be artificially inflated if guests at your resort typically have breakfast credits, vouchers, or coupons. If you believe this is the case, tip 15-20% of your estimate of the market value of your breakfast.