Hi,
I have been here for 13 months and about to go back home. I have two boys one 23 month old and a 6 year old,. Here is what I have found, first hand experience you will need.
The electronics you bring need to be dual electric voltage to work here. Before you come load up on your lap top the tv shows you and your kids watch often. Get a VPN connection too. Tablets, Iphones and so on are good to bring. Carry them on your hand luggage, they can be stolen easily. All other small appliances for the kitchen are not likely to work here, so leave them. Still if you happen to find a dual voltage blender, vacuum, or iron, bring them.
Do buy on sale your sons clothes and bring several sizes worth of stuff here. Clothes back home are cheaper and better quality. However, don't go over board, as it is likely that your boys will have to use a uniform at school here. So if they go through 6 pairs of jeans in the US, buy 2 or 3 for here. They will tear the uniform pants here and not the jeans.
Shoes. Tennis shoes, crocks and so on. Buy them in bigger sizes and bring them. Not only for the kids, but for you too. If you need an insole, or need any type of special shoe for running, hiking etc. Any sport related gear that you know you will use, bring them from there. Here that stuff is more expenisve and harder to find. It is not like you can go to any sport's authority and buy all the stuff you need. Yo will have to visit several stores before you find what you need.
Any type of baby gear is cheaper in the US.
I send my 6 year old son to Islands International School. It is on Belgrano on Virrey del Pino street. They do have expats in the school, but it is not a ton. Which is exactly what I wanted. Since I will be here for a short period of time I wanted a school that was bilingual, had experience with expat kids, but had a small ratio of expats so it would force my son to immerse in the Argentine culture. It worked perfectly. The school is nice, the teachers are lovely, the academic program is good too. I strongly recommend them. It is not an issue if he starts late in the academic yr classes, they work one on one with him to help him with the transition. Very caring teachers.
Toys are an arm and a leg here. Bring the toys your sons like and some more. Hot wheels tracks here cost two to three times what they do in the US. Magnatiles, magformers and other types of magnetic building toys are not sold here. You will find blocks to build, but no lego brand. No Thomas and friends, no Chugginton, few and expensive Star Wars stuff, Jake and the Neverland Pirates is popular but not many toys are available. You will find Angry Birds, Bay Blades, Ben 10, some Ninjago, Bakugan and Pokemon, and Cars stuff.
Regarding food. I have found gold fish crackers, planter's peanut butter, tabasco, worcestershire, fried beans, chipotles, cambell's cream of tomato and tortilla chips at Jumbo/Disco. They have them from time to time and you stock on them. No mac n cheese, no cream of broccoli, mushroom or chicken, no maple syrup, no pancake mix, no frosting, no butter milk, no decent ranch dressing or italian dressing, no cocoa for baking. I think it is unrealistic for you to bring your whole pantry, but you can bring a little bit of something that will give you and your kids comfort. They will adapt fast, but the first month or so will be challenging. So, if they love mac n cheese, bring a few boxes. If they love the casserole you make using cream of chicken, bring a can or two. That sort of deal.
I know on Face Book there are several Buenos Aires Mommy groups. Look for them and join. I have not joined, that is why I am not sending you the invite, but it will be good for you and your sons since they will meet other kids like them and language will not get in the way. It is especially good at the beginning. I found out about these groups late and now we are very settled, so I did not join.
Last, get an appostilled birth certificate of each boy and bring them with you. Chances are you will not need them, but it is something good to heve just in case. If you want to travel alone out of Argentina with the kids, foreign children need their passports, a letter of the father authorizing the mother to travel with them and a translation of the appostilled birth certificate. Just to show you are not stealing your kids from your husband. I know people who never needed that translation, and I know people who did -me included. So, just in case bring one or two appostilled birth certificates and you can have them translated and notarized here.
If you need anything else pm me and I will be glad to help.
Hugs
Pato