MikeyTN has some excellent advise.
While I am not an eclectus expert, I do have some experience feeding parrots. I have been using a sprouted diet along with veggies and fruit for all my parrots. I know that it is like making another meal, but I feel parrot nutrition is very important. Your birds will be happier, they have less health issues and their feathers will have a beautiful sheen to them.
You can feed grains,beans, assorted fruits and particularly root veggies like slightly cooked carrots, sweet potatoes, beets, yams, broccoli, kale, chard, etc.
I also chop up arugula salad mix and add that to their food. I give quinoa and quinoa pasta. Everything that I feed is organic and comes from my local farmers market. I also mix it up each day so they are not eating the same thing each day. The sprouted diet is given everyday but I add a different mix of fruits and veggies each day so they dont get bored of the same thing. Variety is important.
My understanding is that eclectus are very sensitive to their diet and if fed a processed diet tend to lead to toe tapping. Here is an article about toe tapping:
"toe-tapping" in Eclectus Parrot
I have see other health issues which was directly related to diet. About 12 years ago, I had to take my parrot to vet for an eye infection. It was linked back to a poor diet and nutrition. Every since then, I have done alot of research and I have completely stopped feeding processed diets altogether. I do use safflower seeds for training but that is in limited quantities.
I know some people feed pellets and do fine with it. However, I would stay away from any processed packaged diets for an electus or any parrot for that matter. Again, this my opinion based on research and experience as well as seeking professional advise.
Please do not let this scare you from getting a parrot. Prepare everything in batches to last you a few days. I make the sprouts in batches to last me a week at a time. It will become second nature and it really is not that much more work. Below is a picture of what I feed in the morning. When I get home, I do training in which my parrot gets safflower seeds as a reward. I also give fruit or veggies and/or some nuts for him to snack on as well. the seeds and nuts are given in small quantities. This all sounds like alot but trust me, it is easy! I have been feeding like this for about 12 years.
I really can't give you total cost for everything but the sprouts cost me around $50 which includes shipping and 10lbs of dried sprouts. It lasts me roughly 5-6 months for a hahns macaw. Veggies and fruits are not a big deal because I eat them anyhow so I always have them on hand. I keep a large bag of organic Quinoa in the fridge and I keep a couple of boxes of pasta on hand. I wish I had a better cost estimate for you but I don't really keep track of it because most of the fresh stuff is part of my grocery expenditure.
This is a sample of what my parrot food looks like (which is probably the right amount for an eclectus. This is a bit much for a Hahns but I did this as an example so people could see what it looks like when prepared):
And do you have an idea of how much you spend on an eclectus's diet? There's a bird specific store near me that sells bags of food for eclectus parrots, but most people I hear from seem to buy fresh fruit. I'm just curious how much they eat and how much fruit they go through in a day. The seeds and such are easier, and I know they don't eat too much of them.