There is no specific minimum budget for Facebook ads. Facebook advertising is based on an auction system, where advertisers bid on ad placements based on their budget and the competition for the audience they're targeting.
However, as a general guideline, Facebook recommends a minimum daily budget of $1 for ad campaigns that have a specific objective, such as increasing website traffic, generating leads, or boosting page likes. This means that you could theoretically run a campaign with a budget of just $1 per day.
However, keep in mind that the effectiveness of your Facebook ad campaign will depend on several factors such as your target audience, ad creative, and bidding strategy. Running a campaign with a very low budget may limit the reach and effectiveness of your ad, so it's essential to consider your goals and resources when determining your ad budget.
It's important to note that while there is no set minimum budget for Facebook ads, there may be a minimum bid amount for specific ad placements or targeting options. So, it's crucial to monitor your ad campaign's performance and adjust your budget and bidding strategy accordingly to achieve your desired results.