Determining a marketing budget for your Shopify store involves considering several factors such as your revenue goals, target audience, cost of acquiring a customer, average order value, and competition. Here’s a step-by-step guide to help you determine your marketing budget:

1. Set your revenue goals: Determine the amount of money you want to generate from your Shopify store. This will give you an idea of how much you need to spend on marketing.
2. Know your target audience: Research your target audience, including their age, location, and interests. This information will help you to decide which marketing channels to focus on.
3. Determine the cost of acquiring a customer: Calculate the average cost of acquiring a customer through different marketing channels. This will give you an idea of how much you should spend on each channel.
4. Consider your average order value: The higher your average order value, the more you can afford to spend on marketing.
5. Consider the competition: Research the competition to see how much they’re spending on marketing and adjust your budget accordingly.

Once you’ve considered these factors, you can allocate your marketing budget to different channels based on their cost-effectiveness and potential for generating revenue. Remember to regularly review your budget and adjust it as needed.