2 vehicles and a boat

A cousin of mine and his wife is a two vehicle and a boat family and want me to do there vehicles and boat ive seen there car and truck and boat and really there not in that bad of shape as far cleaniness!!! but neverless they want me to clean them up dont really know what to charge. Oh as far as what they want is a complete detail any sugestions:wait Keep in mind this is my cousin im dealing with and he is very picky:dunno

You may just want to offer your help without any exchange of money. That way you can use his supplies and just offer your experience and advice. You can also just help out when it`s convenient for you. In other words, no strings attached. No great expectations.