When presenting the price, it might be beneficial to take the time to explain the different parts of the price and highlight the benefits to them e.g. if they re-licence after a year, they only have to pay the usage fee as the creation fee is a once off cost.

If the price is too high, you can offer to reduce the number of items that they can produce, limit the time of the licence, or restrict how it can be sold. Alternatively, you can reduce the percentage you take, but this is a last resort.

A note on buy outs: These are supposed to be expensive, its purchasing your work and letting them do whatever for however long. They can either have full control and pay a lot, or pay a little and accept the terms, not both.