Exchanges that have listed lumens (XLM).
Coinbase is an exchange with a website and mobile app. This exchange also provides a way to earn lumens by learning about Stellar.
Kraken lists lumens and provides a website exchange experience.
Binance is an international exchage with a web interface, desktop app, and Android app.
User interfaces for the Stellar decentralized exchange that have enabled USD deposits.
StellarX is a UI for the Stellar decentralized exchange. Trade assets that have been issued on the Stellar network or buy lumens via fiat asset issuers.