If you are in a Wi-Fi location, why not use the Wi-Fi directly on the laptop? I do not think that a basic phone can act as either an infrastructure or an ad hoc Wi-Fi hotspot . It can only act as a client to connect to an external Wi-Fi hotspot. If you are talking about one of the Android phones using Wi-Fi to share a cellular data connection, Straight Talk will cancel your account immediately if they find out.
There is no such thing as unlimited Wi-Fi. How much Wi-Fi you can use is determined by the hotspot to which you are connected.