There are other cost effective foods that are better out there. I too have a high energy breed that needs extra and both my dogs I always feed supplements with their kibble such as ACV, raw eggs, sardines and coconut oil. If I could afford it I'd be already feeding a raw diet so I know what it's like when it comes to buying kibble and it's a pain knowing how expensive it gets! I would feed a grain-free diet if your Sibe has food sensitivities with corn, wheat, soy, etc. or even kibble that is potato free even if that. One of my dogs first came to me on Purina as the lady's husband worked there and can't stress enough how much bad things I've heard about that company no matter how long they've been around. If you really like feeding cooked meat and/or raw, I would seriously ditch the kibble and just go 100% cooked or raw fed especially if you can afford to fit that into her diet. Feeding raw in particular has it's benefits as you can control and adjust anything in their diet at a time besides the many health benefits that come with it such as cleaner teeth, shinier coat, better body condition, etc. I also heard that it's almost impossible for them to gain any weight being that they are using more of what they eat rather on kibble which in turn affects the amount of stool they produce compared to kibble.
Here are some lower cost kibble options I would recommend(prices are for the big bags):
- Diamond Naturals(I used to feed this until they changed their formula) $30-$40 range
- Pure Balance Grain-Free(Currently feeding this and it's pretty decent for the price!) $30-$40 range
- Whole Earth Farms Grain-Free(Fed this before too, really great affordable grain-free kibble) $40 range
- Taste Of The Wild(Also fed this, a step up from DN so much better!) $40-$48 range
- Hi-Tek Naturals(Recommended to me before) $40 range
- Earthborn Holistic Grain-Free(Yet another food I fed, highly recommended!) $42-$50 range
- Fromm(Very good, just pricier) $50 range
- Natural Balance Grain-Free(Decent as well, never tried but costs more) $50-$60 range
There's others out there that could be added but you get a gist of some of them.