The cost of developing a simple decentralized application (DApp) based on the Ethereum blockchain with basic features like voting and messaging can vary widely depending on several factors, including:

1. Development team: The cost of development can vary depending on the size and experience of the development team. Hiring experienced Ethereum DApp developers from a reputable development agency can increase the cost, but also ensures a high-quality product.
2. Features: The more complex the features, the higher the cost of development. Basic features like voting and messaging can be relatively straightforward to implement, while more complex features like smart contracts, user authentication, and real-time data processing can increase the cost.
3. Platform: The platform used for development can also impact the cost. Ethereum is a popular and widely used platform, so finding experienced Ethereum developers can be more affordable than other blockchain platforms.
4. Design: A well-designed DApp can improve user experience and increase engagement, but also increase the cost of development. The cost of design can vary depending on the complexity and type of design elements required.
5. Location: The cost of development can also be impacted by location. Hiring developers in countries with lower cost of living can reduce the overall cost, while hiring developers in countries with higher cost of living can increase the cost.

Based on these factors, the cost of developing a simple DApps with basic features like voting and messaging can range anywhere from $10,000 to $50,000 or more. Ethereum DApps development services can provide a more accurate estimate based on the specific requirements of your project.

It's important to note that the cost of development is just one aspect of building a successful DApp. Ongoing maintenance and support, marketing, and user acquisition can also impact the overall cost of a DApp project.