ThemeForest item - One Time Fee?

I want to buy this theme: Discussion on DW Timeline Pro - Reponsive Timeline WordPress Theme

I have some questions: can i use this theme with one payment? So this is lifelong purchase? It will be another payment after one year?

And “Last Update: 1 April 19” it seems so old, is it problem?

It is one time payment and you can use it on 1 website/installation and you have 6 months of support. After 6 months you can buy just additional support if you need it. You also get a “lifetime” updates for free.

About last update - Yes it can be a problem. The bigger problem is this:
Software Version: WordPress 4.9.x

The latest WordPress version is 5.6, and I am suggesting you to contact the theme author and to check if the theme is working with the latest WP version and will he keep updating the theme.

thank you so much