Best tool/library to generate PDF documents in .NET?

At my job I need to make many documents like tickets, bills, contracts in PDF format, some of them have a quite complex design. I would like to create bunch of templates and then fill them with data from json, xml files or exported from some remote database.

I mainly work on .Net apps and do programming in C#. I found some solutions online, but I don't know which one to choose, most of them seem to focus on just converting from other formats like html to pdf, but I need to basically create PDF files from scratch with code.

I wonder if anyone encountered such need and would be grateful for any suggestions for a cheap and easy-to-do solution from your own experience.