Re: dubai visa
If you are a US citizen you will not need any sponsorship from your family there. Just go to the immigration counter directly and they will stamp a 30 day visa into your passport. No additional requirements like hotels, sponsorships, etc.
If you are a Pakistani citizen traveling on Emirates, then the most economical option is to get a 96-hour visa through the airline. However if you are not traveling on Emirates that will not be possible.
In that case your relatives there would have to sponsor your visit visa which is valid for 30 days and is much more expensive than the 96-hour visa you would get from Emirates Airline. For that you would have to send a copy of your passport + a passport sized photograph to your relatives. They would then have to go to the DNRD office along with their own passport, their income statement (there is a certain income required for sponsoring visit visas) and the documents you sent them. After paying the visa fee, they can collect the original visa (a pink coloured A4 page) after a couple of days from the DNRD. They then have to send a scanned copy of the original visa to you. Make sure you have a printout of that with you when you leave the US. Your relatives have to submit the original visa at the airport a few hours before your arrival. Once you arrive in Dubai you would have to go to the visa collection counter, get the original visa from there, go for an Eye Scan and then to the actual immigration counter.