You can exchange PART to Bitcoin at any time with WizardSwap (KYC-free), so you don't need to hold it. There are no active decentralized marketplaces yet for Bitcoin (sadly Mobazha.info has few sellers) so Particl could be useful.

If you want to use Bitcoin only, there is an active Telegram marketplace for products/services: https://t.me/BitcoinP2PMarketplace and some new centralized marketplaces: https://tukan.market and https://miragesale.com