You can easily post your ad; Just tap on the the plus (+) icon & then login and submit your ad with proper data. You will get a notification after submitting your ad.

There are no limit on days but the number of ads you can post for free has limits.

Yes. For chat request or email, seller will get an email notification. For chat, buyer will get first initial message as email notification

Apart from showing on Top of the site and apps, boosted ads are also advertised on google, YouTube, Facebook & Instagram.