since you stated you have never made one before- maybe before agreeing to this you should make yourself one- even a smaller-throw size one- so you 'learn the process' and see just what it does take- then you would have a better idea how long it would actually take and the difficulty level- you say its a 'simple big block quilt' but ... a t-shirt quilt is a whole different 'animal' than a regular cotton big block quilt! you may find you do not like working with t-shirt fabric, that it is a much bigger *pain* than you anticipated...(or of course you may find you love it & want to make lots of them) either way you will be basing your decisions on knowledge. $8 an hour is not reasonable- it is not even minimum wage- and you really need to value your time if you are going to start making quilts for sale. doubling that amount would not be unreasonable..... but make at least a big pillow- something with a few t-shirts before committing to this project.