Breaking the lease should also forfeit their deposit.

I use a Holding Receipt and Agreement that states we are holding the dwelling exclusively for them until a certain date and it will convert to security deposit funds when they sign the lease and move-in but will be forfeited if they don't.I don't like the word deposit, like holding deposit, because deposit can mean refundable. 

In a lease it states if you want to leave early from the lease, “if you move out before your lease expires and you provide a 30 day notice you shall be liable for one additional month of rent and shall forfeit security deposit.”

If they don't do everything required of them, they forfeit the holding fee as liquidated damages and the lease is cancelled and the property will be re-listed.  

After that, they forfeit the deposit.

If I were to leave this year (preferable for me if we can't agree on a much lower purchase price), it actually would be cheaper for me to pay the 20% premium monthly until I leave, rather than an entire year's lease at 3% increase until next April; I'm just wondering if this is an option or if I've forfeited this by paying the 3% increase and implying acceptance of the 1 year lease renewal.

Usually means you forfeit your DP.  

It Makes 1900 per month.Do I walk away from this deal and forfeit the money I have put out for deposit and miscellaneous expenses or do I take the appraisal on the chin and take over this property in the negative?

Thanks in Advance...please know I am looking for advice not simply an invitation to speak with you Also i'd like to stress that my younger brothers and I are are willing to forfeit our share of the profit so that our older brother and his family have an affordable place to live.

If you decide not to purchase the property after the seven year period you forfeit the purchase agreement deposit and you will need to vacate the property.