implement/advise Multi-channel Marketplaces, Comparison shopping and paid search

I currently sell products on ebay and would like to expand my products to all market places, comparison shopping, paid search, etc..... I understand that there are many ways to accomplish this; there are free solutions and paid solutions( such as channel advisor but seem to be very expensive). Ideally I want to input product in bulk into one system and then have them push to every other channel automatically or manually with little effort. Sounds good in theory but I have been research the options for months now and come to understand the complexity of the situation. I am familiar with wordpress, hikacart and other CRMs. I also understand that there are some free solutions to help with some of the marketplaces and also understand there are paid solutions that can theoretically do all of this as well as sync data and inventory, however they are very expensive. The items that I sell are things that I buy in bulk or dropship so the need to have inventory levels synced with all the marketplaces sounds great great but are not actually necessary. What I want is to be able to input for example a spreadsheet with thousands of items into one place(weither its a ecomerce solution, ebay or a program on my computer) then have this data push to every free marketplace, comparison, etc. Also push to places that cost money for listings.. I would like to have a system that is opensource or pay for it once and own it solution to do this. I understand that there are some free solutions and some paid. I really want to stay away from a monthly payments for a solution. I am hoping to find someone that has already done this and can advise me how to do it best. It is okay if it requires multiple solutions some free some paid, maybe some custom. I just cant see myself paying some company like channeladvisor $1000s a month when I know most of this can be done for free or with a couple inexpensive solutions mashed up together. I may actually just pay someone for the advise if they can tell me to use x,y and z to make this happen, I am willing to do the work but I need advice from someone that has done it. I also understand some of the solutions will cost money to pay for pre-existing programs, codes, solutions. I simply want an advisor to tell me what to buy, what to setup and help with setting up simple code thats free but beyound my expertise, such as a data feed to google, bing, etc. Please Send an offer for the cost to advise me and also the cost for the softwares/solutions to buy for a one-time fee or cost per month if needed for a service.