We suggest to use the Booked – Appointment Booking for WordPress which is relatively affordable and it does have a lot of options to configure. It does look modern and it has a popup option. There are many plugins available on the market.
Also bear in mind that you might want a plugin that integrates with woocommerce checkout. This is because you can integrate your local payment method which will most likely not be supported by plugin itself. Polish PayU is a good example of that. It does have woocommerce integration but none of the plugin supports it directly.
Amelia is also a good choice. It is more expensive but it does offer lifetime developer plans (around 3000 zł) so you can save up if you make more then one install in long run. It also have woocommerce integration so you can very east to use external payment getaways like PayU. This is really a great option worth considering.
https://wpamelia.com/woocommerce-integration/
Sometimes those more expensive are not worth a single dolar like Booking plugin from WooCommerce. If you want to get to know other options watch this video:
