You can only save heirloom or open pollinated types if you want them to grow "true to type" like their Mum and Dad*** these are all varieties except hybrid F1's. If you save and sow F1's your toms won't grow like their parent(s) - they'll be F2's which for tomato plants are probably going to produce something different.
Moneymaker crossed with Gardener's Delight = Money Delight
At this point I should suggest a competition for the most amusing cross but I'll resist that!
How to Save the Seeds
Remove the seeds and juice into a glass or small container and cover with cling film etc and add a little water... just enough to cover the seeds.
Keep for about a week during which time a mold will develop called a "mother". This mold will sterilise the seeds.
Rinse the seeds then put them into a glass of water ... the good seeds will sink and the bad seeds will float. Dry the good seeds on kitchen towel for a day or so, until they are completely dry then store in an airtight container such as a container for vitamin pills etc.
*** Tomato plants have flowers that are self-pollinating, that is, they don't need another plant to fertilise their flowers. Although, sometimes a Bumble Bee can cross fertilise one variety with another - as above.