The image of a cash register often means limited access to the world around you, which is blamed on money. You would rather have more than be more, indicating greed.
On the other hand, the cash register is a place where money is kept in an orderly fashion, protected and saved. In this case, Money is a symbol for your abilities and talents.
Folklore: Good omen, prosperity.... Little Giant Encyclopedia
A cash register may signify that it is time to cash in on a business deal and usually is a sign of money coming in. On the other hand, it may be related to your concerns about making a profit in business.
A cash register whose drawer is stuck may remark on your inability to make money.... Ariadne's Book of Dream
To dream that some one registers your name at a hotel for you, denotes you will undertake some work which will be finished by others.
If you register under an assumed name, you will engage in some guilty enterprise which will give you much uneasiness of mind. ... Ten Thousand Dream Interpretation
If you dream of registering to vote or of signing up for something, then this represents a willingness to allow that, which you’ve signed up for, to influence your life. Consider what you are registering for so that you can understand what you are subconsciously saying “Yes” to.
If you dream of a cash register, see Cashier.... Strangest Dream Explanations
Dream Interpretation
Islamic Dream Interpretation
Common Dreams