We have 6 cars for 3 drivers. We're a 2-income household, and we have solid incomes but are not rich.
None of our cars is very new. Newest model year car is my wife's 2004 TSX, bought new in 2004. Next is my 2003 325i, bought used in 2006. Then there's my daughter's 2002 Impreza wagon, bought used in 2009. We have a 2000 Grand Caravan, bought used in 2002 or so. My play car is a 1996 Miata, bought very used in 2010. Last but not least is my 1967 Le Mans, bought new (for my mother) in 1966.
Out of all those cars, we borrowed money only on the Acura and BMW (something like 50% of cost for each), and they have both been paid off for years. Most expensive were the TSX at $26k and the 325i at $22k. Everything else was paid for with cash and cost between $5k-$10k. The '67 Le Mans was more or less given to me as a driver in HS in the early '80s and has a lot of sweat equity in it, if not much cash.
Nothing is planned for replacement for at least another 4 years, barring the unforeseen (an accident prompted replacement of our 1992 Caravan with the newer GC, otherwise, we'd still have that). We keep cars for a long time and only replace them through attrition. We'll probably add a 7th car in 2-3 years after my younger daughter has had her license for a while.
The main trick we use is to have a car payment withheld from my wife's paycheck every month, even when we don't have a loan. Her TSX has been paid off for at least 3 years and we now have almost 50% of its new replacement cost sitting waiting in her credit union account. By the time we actually shop a new, similar car for her 3-4 years from now, we'll have probably 80% of the price in hand, plus the residual value of the TSX.
Insurance runs about $3200/year for full coverage on 5 of the cars (the Pontiac is only covered for comprehensive and is not currently registered) counting a 19-year-old female driver who is more than 1/3 of that by herself. We take advantage of multi-car discounts, defensive driving discounts, good student discounts for my daughter, and discounts for having homeowners and life insurance with the same company.
Most;y it's a matter of budgeting savings in preparation, buying good-value cars, keeping them for a long time, and avoiding payments where possible. I'm not allergic to financing cars if the rates are decent (we've financed 4 cars in 19 years), but we avoid loans longer than 36 months and we make sure they get paid off early if possible.
I do all my own routine maintenance but I'm not up to complete teardowns, in either skill or facilities. Since I have spare vehicles, I'm willing to tackle timing belts, etc. since I can take a car off the road for a week without stranding anyone.
My biggest issue is parking. Right now I have 2 in the garage (the Le Mans and Miata, both ragtops), 2 in the driveway (TSX and 325i dailies) and 2 in the street (GC van and Impreza). I really should part with the Pontiac and get the 'van back inside - if I can get it back under cover, it will serve its function for another 10 years with ease.