Any of the options for commissions in this website (portrait/custom illustration/fan art) has its Low Cost version. In a more simple style, nearer to comic style you can get a good quality artwork at a good low prize.
Technic: graphite pencils.
Picture of the person or people to portray and anything you can show me to know the best your idea.
To make your custom illustration THE IMAGE REFERENCES ARE VERY IMPORTANT TO GET YOUR IDEA AS MOST FAITHFULLY AS IT'S POSSIBLE.
They're a great support to portrait anyone specific, design outfitts, create a background if you want, hairstyles...
NOTE: Every drawing will be top off with a special fixer that will keep your drawing in perfect conditions forever.