You can expense anything you pay towards advertising or marketing your side business. This includes the cost of activities like market research or free samples.
Detail
Advertising and marketing costs can be expensed, for example:
Social media advertising
Market research
Flyers (printing, design)
Free samples
Gifts of up to £50 (they can't include food, drink or tobacco and must be advertising your service/product in some way)
These expenses might be relevant too
Website
The various costs that are incurred when you set up and run a website for your business can be claimed as expenses (e.g., hosting costs and domain name costs).
Read more
Allowable?
Risk level?
Allowable 🟢
Low risk 😃
Utilities
If you have separate business premises, you can claim the full cost of utilities for that space. If you work from home, you may expense a portion of your bills.
Read more
Allowable?
Risk level?
Possibly 🟡
Low risk 😃
Travel
Expenses you incur when you travel for business can normally be expensed if you're a sole trader. This does not include costs of travel between home and work.