I am fairly new to planted tanks myself. I have a 30l which I use liquid carbon and tpn+ for the ferts. I dose around 1.5 ml per day as I have quite high wattage of lighting (24w). Best bet would be to decide a) if you can afford the time and money to get the extra equipment and b) what plants you actually want. If you want plants like annubis, java fern, vallis etc then you will not need the carbon and ferts. On the other hand, if you want to go full out with Hemianthus Callitrichoides or Pogostemon Helferi as a carpet plant then you will need the extras.
Once you have decided on the final product you want, have a look through the planted forum (bit further down on the main page) and ask there. Everyone there is friendly enough
The other option is to use cat litter as a clay layer then top it with something like JBL Mandano. The clay texture absorbs nutrients and releases them slowly over time.