Let's start with the latter. Unless a fancy tip is required, most people have the means to MacGyver a pastry bag right in their kitchen. Any resealable plastic bag will do, but some brands are stronger than others and will hold up to a stiffer mixture. Pick one of the bottom corners and snip it off to the right size after filling and voila, instant pastry bag. Even if you need a tip, it can be dropped into that corner prior to filling and works just the same.
|Um, no, I don't think that's too many pastry tips. Why do you ask?|
As for how hard it is to use one, that's a matter of opinion and practice. There are lots of tricks you can use to make the experience less stressful. A paper clip behind the tip will seal it sufficiently while filling and between uses, for example.
While using, the tip-end hand should be to guide the bag and the back hand controls the pressure. Using the tip to manage the flow results in product flowing out the back of the bag. The tip hand can stop the flow by folding it upward if things start to get out of control.
Most of my recipes that require a bag use a plain tip, which is the same thing as snipping the corner off a ziplock unless you have to use it to puncture something you're going to fill. I don't even know what all my tips do, and I'm awful at using the Rose Nail. I'm a bread baker, not a pastry chef. And yes, there is a difference. That's why they have two different terms for baker in French. I suppose I could take a cake decorating class. Michaels sponsors them, I live in driving distance of several culinary schools, and one of my friends is awesome at it.
So, the next time you see a recipe that mentions pastry bags, don't panic. I bet it's something you can do.