Joe Tausch, Broker BA, MA San Diego State personally owned over 20 businesses. Business Opportunities Unlimited has specialized in the sale of businesses in San Diego County since 1973. One of the largest business brokerage in San Diego. Over 25 experienced and knowledgeable agents with experience up to 28 years. Largest inventory of businesses in San Diego. Hundreds of repeat customers attest to the fact that they are satisfied with our services.