Planted tanks are not difficult one bit if you research BEFORE and match plants to your water/situation.
For example, I have a 6500k 10watt daylight bulb in my 5 gallon so it's pretty moderate/high light. Therefore my 5 can hold a large variety of plants due to such light.
My water is very hard, so I don't buy soft water plants (like banana plants..aw). I know in my 2.5 it will be taken apart monthly, so I chose a plant that doesn't root. (Hornwort). Other plants are mosses, java ferns, moss balls, anubias, etc!
In my 10 gallon I have 'moderate' light (soon to be high, I hope) so I used lower lighting plants. Because I will never take it apart, so I used rooting plants that are more 'sensitive' with root tabs.
I use large sized gravel. No substrate fertilizer. Just liquid fert and root tabs!
Liquid Fert- $10-20 (Depends on type/quality but lasts FOREVER. Mine has lasted 5 months.)