Here is what I tell anyone who gets into any hobby like this. This also applies to buying a car or computer.
Figure out what is the max you can invest and then get the best stuff you can in that budget. And maybe I missed it, but do you plan to have fish?
Stuff you need:
Get yourself a decent filter. Doesn't have to be an $100 filter.
Heater and Thermometer -
You may or may not need these, depending on your needs and room.
It can be tough to find a 5lb bag for your needs, and all you need is 5lbs, and I doubt you will use that. I used Petco Sand for $5 in my 4gal. And still didn't use the whole bag LOL.
Figure out what plants you want. You will easily spend $30 on plants, trust me.
Do you plan to have fish? You need to decide now. Remember, it is only a 5gal,. you can't pack a bunch of fish in there.
I do not normally support going to Amazon over a LFS, but Amazon has the API Master Test Kit or whatever it is called, that is normally $35 to $40 in my LFS for only $20, which is a steal IMO.
If you are going to have fish, you will need a water conditioner. You may or may not need root tabs, or a liquid fert. You might need random tools at some point. I have a betta in mine, and find I will need some sort of long tweezers to pick out dropped food, once it is cycled.
My biggest advice, STUDY! Read up on here, read the articles, FAQ, stickies. Watch peoples posts. You will see others starting exactly where you are every day on here. Read their posts, see what people are telling them. Go to the library, get a book. Or find some articles online. Read about the plants you want to keep, the fish you want to keep. Read about cycling, but do not get overwhelmed by it, it is way easier than some people make it out to be. Patience is the key.
You have one of the best tanks, or at least show tanks, out there. So people may see what you are starting with and assume you have deep pockets LOL.
It can all add up really quick. I have spent nearly $200 on my setup.