No fee is payable for lodging an appeal, except for an appeal against an enforcement notice where ground (a), that planning permission ought to be granted for the development, is pleaded.
For all planning appeals, either of the principal parties (i.e. the appellant(s) or the planning authority) can make an application for costs to be awarded against the other principal party in the appeal or, exceptionally, against a third party, if it is felt that there has been unreasonable behaviour, leading to unnecessary or wasted costs being incurred. Normally, the same Inspector who determines the appeal will also decide any costs application(s); using the National Planning Practice Guidance as a guide to what constitutes unreasonable behaviour. Planning Practice Guidance contains information on the award of costs.
If you use a planning consultant or other professional to present your appeal, you will, of course, need to pay their costs.