First I want to say that I am proud of you. I love to see young people learning a craft that will reward them all their lives. Here is a website with a free pattern that I like a lot.
Just click on the words "knitted baby sweater" highlighted below the picture. This pattern is free, attractive, and not too hard to make. Cotton yarn is suggested, but you can use any yarn with the right gauge.
Cotton yarn is cheap and easy to get if you recycle old cotton/ramie sweaters that you buy in thrift stores. You just pick them apart and unravel the yarn. First wash the sweater, then pick out the seams, and then unravel each piece. It is just like knitting, only backwards. I have had excellent good luck with recycled cotton ramie. Make sure that you wash the thrift store item before you recycle it. You don't want to handle old dirty clothes. You can recycle a lot of sweaters this way, cotton or other materials. Look online for free tutorials on yarn recycling, or ask another question and people will tell you about it.
I disagree with the previous answer that books and libraries are useless. It is possible to find good patterns in books, and I have found great patterns that way. Simple Knits for Cherished Babies, a book by Ericka Knight, is full of excellent easy to knit baby patterns. It is possible that you could find this book in a library, or you can buy it.
Also the Elizabeth Zimmerman books have some excellent standard baby patterns. Elizabeth Zimmerman's patterns can be challenging to follow, but I bet you can do it. If you have trouble, you can go to your local knitting store and ask for help, or ask someone in your family who knits well to help you. You just do exactly as she says, even if you don't see where she is going with that. The pattern called "Baby Surprise" sweater is great, and you can see it all over the internet. The sweater is all over, but you have to buy the pattern or find it in your library. Her books are often available in libraries for free. Ms. Zimmerman's patterns may not be what you need right now, but you do want to see them. They are interesting because of her cool and innovative techniques, and they will make you a better knitter.
Screen Printing companies online have different ways for charging and ordering. Look for a company who has all inclusive pricing with free set up,screens, and shipping. The key is to find a company who offers bulk screen printing cheap and includes the kids and adults shirts as the same order. Alot of company's will make the kids shirts a separate set up from the adults and that will bump up the price of your order. You also need to be able to add all of your items in the shopping cart and then get your discount rate for ordering large amounts and different designs.
We have had great success with a company from Massachusetts called
http://www.cheaptees.org . They allow you to use different designs and different shirt styles and put them together in the cart. This way you get a large discount for combining all of your screen printing. They also do real screen printing. We first found this screen printing company after we had some real bad experiences with companies who offer direct to garment printing. Although the other companies allowed us to mix everything up they still turned out to be more expensive in the end. This is what you need to look out for. Although these companies say free set ups and other things they really never give a large discount for big orders.
We found the quality of cheaptees to be expellant and we still have shirts that we purchased several years ago that look good. We found real screen printing holds up much better cause the inks won't crack,peel or fade like other methods. I purchase for our school and our kids soccer team so I got alot of experience with this sort of thing.
When looking for cheap silk screen companies you also need to ask if they print the dark colors once or twice. We found that alot of companies charge for what they call a flash if you want the to print the dark shirts with two coats of ink. The company I mentioned above,Cheaptees Screen Printing does not charge for coating the shirts twice and we have loved how the shirts come out when they print on the darker colored shirts.
You can also upload your artwork on their design tool and then see what it looks like before ordering. They have a real cool section called single color screen printing where if you have your own designs you can upload them and although you cannot preview them right away you save a ton of money on that part of their site. The shirt styles on this section are limited but they are all the best styles you can find anywhere. The good thing with this section is you can order a single style and you are able to order from kids small all the way though adults larger sizes all on the same order. They do not charge extra for the screens so if you need kids sizes just make sure you tell them you would like different screens for the adult as well as kids. This way your prints will look proportional according to the sizes. If your order is large enough they will not charge for the kid screens. I believe if you order over 100 shirts they will not charge for the extra screens for kids.
Cheaptees also will send you a proof of what your shirts look like before they print the order. They send the exact shirt as a mock up with your ink colors on the shirt. We have had some issues with the colors but it really has turned out to be our monitor and not their fault. So just be sure of your ink colors before hand and you should not have any issues there.
Another thing they do really good is really fast shipping on their shirts. We are in California so it takes about 5 days on UPS from them but if you are on the east coast you can probably get your order in about a week or less. They offer a shirt called Port & Company and that shirt is the best we have ever received from any company. It is much better than the Gildan which is about the same money even a bit less than the Gildan. You will only find that shirt on the single color section so if you need more than one color printed,which we do, just give them a call and they take our orders over the phone.
You can order from them at http://www.cheaptees.org