Re regens - in addition to what has been said above, if you decide to play with one, do make you build one of the "decent" designs that have an amplifier stage in front of the regenerative one and good bandpass filters before connecting any sort of antenna to it. Otherwise you are going to produce a ton of nasty interference which is coincidentally why regen designs are banned/heavily restricted in many countries. Possible problems with the authorities aside, causing QRM like this is just bad juju and it won't gain you any friends on the bands.
Had an out of topic question. Have any of y'all built a DDS VFO .Had a thought to build one with Si570,but can't source one fir cheap. Any idea about the exact price of them?
Sure, e.g. mine on my website (tooting my own horn):
https://janoc.rd-h.com/archives/502But there are plenty of designs around the net, pick based on features you need and the way you are planning to operate it. E.g. my code doesn't have band switching but it allows continuous tuning in the entire range without twisting your hand off while operating the encoder - good for a receiver or generator. Other versions are more radio oriented, with explicit support for multiple bands and modes.
I wouldn't do it with Si570 unless you explicitly need the high frequencies it can reach - it has only a single output and is not particularly easy to program because it isn't really a DDS synthesizer but a PLL. AD9850 (DDS synthesis) modules can be had cheaply and have sine output, another popular choice for superhets is Si5351 (a PLL clock generator) which has 3 square wave outputs (depending on the version can have up to 8 ), so you can easily build both a VFO and a BFO with it. If you don't want to solder tiny parts, modules are also available (e.g. from Adafruit).
The Soldesmoke guys (Bill Meara & Pete Juliano N6QW) have a ton of resources on homebrewing this stuff - both in the podcast and in Pete's blog. He is a prolific radio builder:
http://n6qw.blogspot.com/ (usually work in progress)
http://www.n6qw.com/ (once done he moves it here)
Bill's SolderSmoke podcast site:
http://www.soldersmoke.com/