Ted - I am a realtor and work with investors as well. There are a couple of ways to buy wholesale - if it is just a conventional sale (that includes REO, foreclosures, etc), you must have a preapproval/proof of funds. Talk to your lender first, see what you qualify for, and also how much equity you have in your house - you MAY be able to use HELOC with the right lender for the purchase. Another way would be to immediately resell the property at significantly below market value to another investor/RE portfolio holder and make less money, but in much shorter time - you would in essence be selling a note. That would not require funds, but it is a more nuanced transaction. There is a number of hard money lenders in Milwaukee, they all require that you use some of your money as well to have "skin in the game". They will issue a proof of funds letter if you meet their criteria. You definitely want to join local REIA chapter, all HML as well as a few wholesalers are very very active in the group.
You also want to ask your realtor to expand the search outside of just foreclosures, since there are deals to be found on MLS on conventional listings as well (mostly probate, divorce, preforeclosure, short sale, etc), and many times that would actually save you money since the homes would be in functional condition, as opposed to foreclosures, which in portions of Milwaukee require more money to fix them than the purchase price.
Hope this helps, and best of luck on your first deal!