Making high-quality prototypes:
Prototyping a card or board game can be as simple as cutting up some printer paper and marking up the bits with colored crayons, but while this is OK for testing the functionality of a game, product acquisition folks expect and appreciate a bit more effort and polish.
It's great if you have a background in illustration or graphic design, but for the rest of us, I recommend using the web as a resource for finding icons, patterns, or other graphics. For the games I create, I tend to leave them as abstract as possible so the licensor can apply whatever property they want to the game - like swapping in various Pokemon characters for primary colors in a matching game. Sometimes however you need to find photos or illustrations of your own characters that need to be less abstract. For this I search for images in a similar style or people in similar poses so they work together as a cohesive whole.
Don't worry about 'stealing' someone else's work for your prototype, but make it clear when you present that you are using images found on the web that you don't have the rights to and can't be used in production. If you're worried that isn't enough, or the images you find aren't looking very similar, try using some of the creative image filters in Photoshop to make them look hand-painted or pencil drawings. Adobe creative suite is only $53 for a month, and if you plan out your work, you can get a lot done in that amount of time. There are tons of tutorials on YouTube to help you get started.
While Photoshop is great for altering regular images like photos, I use Illustrator to create most of my graphics in what's called 'vector' format. This means the image, graphic, or icon is made from lines, boxes, circles, and squiggles that can be grown and shrunk without losing any detail. For example, if you zoom way in on a JPG photo, you'll eventually see little squares of color making up the image whereas if you zoom way in on a PDF, AI, or EPS file the lines just get bigger and smoother. There are even tools for converting simple 2-color graphics into vector icons built into the application.
Lastly, when it comes to printing, you don't need to buy a $600 color laser printer - it probably won't be able to do what the industrial ones at Kinkos can anyway. It's about $1.50 a page with heavy paper to get a 8.5 x 11 inch, single sided sheet printed there. I've never had much luck getting the images on front and back of a page to line up quite right, so I usually glue together two thinner sheets to make nice looking cards. Double-sided tape, spray-glue, and even glue-sticks are all you need to put things together, but the real cherry on top of the cake is using a corner cutter to make all of your cards or tiles with rounded corners. I have a nice one I got from a local craft store that does three different sized corner curves and the difference it makes is amazing.