Unfortunately with bartering you still have to pay tax on the value of your services but you can reduce those taxes on that barter by giving each other a 90% discount. The tax people won't like it but I think its all legal and even if it wasn't I don't know how they would find out or prove it.
This is impossible without knowing a whole lot more about you. It's rather like calling an insurance company and asking how much it will be to insure a car without telling them what sort or car, how old you are, what your record of accidents is .... you get the idea.
You should speak to an accountant but make sure it is one who does understand your type of business, your personal circumstances, and the tax opportunities these offer. Not all do.
Their are lots of legitimate ways of saving tax - I can only really echo what others have said, get a good accountant on board and let them review your tax affairs in detail. Its a fairly routine thing a good accountant should do on an ongoing basis, and will certainly be something a new accountant will do for you. You will probably find your fees will be money well spent.