I think you should always pay for stuff that people create for you. A lot of people don't like to pay for art and this is just unacceptable. Artists are putting a lot of work and thought into something and they should also get something in return as well (apart from recognition). I also get asked a lot of times, whether I create customized music tracks for free but I never do, and I think no one should. Everyone has to pay their bills.
Be nice
Pay the artist!
That is exactly what I was going to say. I am working on my upcoming gaming channel and I have hired someone to make a pixel animated intro for me, and I've also contacted someone to make some chibi designs and asked for a quote. Artists put a lot of effort, time, and hard work into what they create, and they deserve to be compensated for that. Would you not want to be paid for a job you have done?
I do not have much money, but told the person I hired for the intro that, as I valued their work, they would be paid. The quote he gave me was very reasonable, he mentioned that he would be ok with me splitting the payment in whatever amount I was able to pay, and he also said that he would still give me the final product even if I hadn't finished paying. Furthermore, even though we've agreed that I would make the first payment at the end of the month, he already sent over a rough draft of what I asked.
It's all about how you present yourself. If you show people respect, they are more likely to return the favour and willing to make compromises that would work in your favour.