I have some experience with developers in Poland, and know people who work with developers in the Ukraine.
I am assuming it is more like facebook and twitter than
http://www.watchshop.com, which you can do with wordpress + plugins or for example
http://www.shopify.com .
A good Polish developer will want something like 3k/mo. There is competeition in EE, with top software companies (Google, Microsoft, CDPR) sparring with local startups and businesses to snap up the best talent. If you are not fluent, you will need a contact who is fluent and savvy to get good talent. You will want to recruit at the local colleges, and you will have to train the talent.
Otherwise, you can go online. Depending on the complexity of the project you may want to hire a complete team which already has the qualifications. A team of ukranians can cost 5-6k/mo. This is for work done remotely.
If this is not on the scale you are looking for, look into wordpress or shopify. Most ecommerce sites can be done with wordpress. Buy a theme and use a payment platform like stripe. Also If you can't write the code yourself, put up leaflets at the local community college and hire a temp.