With the africans remember to get a log book. They require a higher ph in the water because of the lakes they come from lake malawi. Check whatever water source youre going to use and check if the ph is going to be appropriate. For example if your water source is going to be low in ph you know youre going to have to add stuff to get the right ph. If your ph is high already you may have to add stuff to lower your ph.
Another thing to remember with africans is when you get them they are little half inch or so. Remember that some of those bad boys get pretty large. So the tendency is to fill it with them when theyre small, just make sure you keep in mind what that tank is going to look like when theyre all 8 inches to foot longs.
When theyre smaller youre going to want to setup lots a little caves and hidy holes for them. They are aggressive but in a few days time you'll notice which ones are the Alpha fish and which ones are more subserviant (sp). Theyre a lot of fun and a very sought after fish for home aquariums for their bright coloring. Theyre awesome fish and have great personalities, just seriously keep a log book of the ph in the tank. That way with the log book, you'll get a good understanding of how your ph goes up and down with feedings, or with additions of water or any changes etc.
Prices for gear etc, are pretty leveled out across most places you can purchase from. This is one of those times where if possible its best to find a place near home to purchase because you can always go back for adivce help etc and you've already got a working relationship with the folks at the shop.
The suggestion for the plecostamus was a good one. They are excellent tank cleaners. Another fish I would suggest to clean your gravel real well would be a st. raphaels catfish. They do pretty much the same thing as the pleco, and to start off they'll be about the same size.
Run your tank for atleast 3 days at the proper ph, before introducing any fish. Sterilize anything you add to it. When you introduce fish, try to add them at the same time. If you get the fish in bags, from the petstore, take half that petstore water out and add half from your tank to the fish bags. float the bags across the top of your tank for 1hr.
1 hr goes by dump that water and fill all the bag with water from your tank. You're trying to get the fish used to your water, and at the same time purging whatever was in the stores water. I know it seems like overkill, but your're basically creating a sanitized enviroment for these fish and you dont want to introduce anything to get them sick, any food left over in the stores water bags and waste etc. If you need any help etc let me know I'll be glad to help. I've pretty much run tanks all my life, and I've raised fish from frye to being 18 and 22 inches in length
oh and dont place your tank in a place where it will get direct sunlight. This will cause nasty oxygen robbing algae blooms.