To give an item a good reasonable price, you need to answer three major questions:

1- What is the real cost for this craft item?

You need to calculate the exact cost of each material you used in it. If you just only use a small amount of yarn for a crocheted mobile phone cover, for example, you shouldn't add the cost for the whole ball.

Although you must use materials of good quality, that doesn't necessarily mean they should be costly. Buyers don't pay for the material they pay for a finished item.

Calculating the real cost for your masterpiece, you must add a fraction for your effort and time, and that fraction depends on the next two questions

2- Where are you going to sell it?

This is probably the most important question. A knitted sweater may be sold of 0 at a top famous store. While the same sweater may not exceed at a local shop.

3- Is your item unique and highly demanded?

People who appreciate handmade items may pay a good fair price. Some of them may be crafters and know the big effort needed to finish such item.

You must put in mind the type of people you're going to deal with. A couple preparing for their wedding may be willing to generously buy a bridal garter. Same as to selling red crocheted flower bouquets and hearts on Valentines day

If this is your first item to sell, you certainly need to give a low encouraging price because selling an item is really an achievement at this stage. I'm sometimes willing to giveaway a new item as a test drive. I certainly rely on the word of mouth to get some good reputation