Bitcoin transaction fees and exchanges When Bitcoin started off, I thought one of the advantages was that there was very little transaction fees. However , now to send bitcoins to another address(exchange independent), I have to set a rate for it to be included in the blockchain. At some point when there are so many transaction, but miners have reduced, would the transaction fee not become very high?

The second question I have is what are the good decentralized exchanges(like bisq), but which do not require any bitcoins for me to start? It seems to be that the price on localbitcoins is pretty high compared to exchange rate. How do I find someone who is ready to sell me some bitcoins at the market rate and avoid exchange fees(different from the transaction fees I talked about earlier in the first question.)
Bitcoin was never really meant to have no/low transactions fees.  What was always intended (and still is true) was to have market driven transaction fees.  In fact, as block rewards grow smaller, the plan has always been to eventually compensate miners from fees alone.  Because transactions take up space in a block, and block space is limited, there is a basic economic supply/demand curve at work.  There are many improvements being made to shrink the space that a transaction takes in a block, which effectively increases the supply.  However, as Bitcoin becomes more popular, demand is also on the rise.  In addition, there are layer-2 solutions such as the Lightning Network that only uses the blockchain for settlement, and performs off-chain transactions for common use.  This could also increase the supply, but may also increase the utility enough that demand also skyrockets.  There is a long-standing debate about how to scale Bitcoin, and your question about transaction fees sits right in the middle of it.

Concerning your inquiry for decentralized exchanges between Bitcoin and fiat currencies...


  How do I find someone who is ready to sell me some bitcoins at the market rate and avoid exchange fees


You are trying to have your cake and eat it too.  If you don't want to pay fees, don't expect market rate.  That market rate is really the "market with fees" rate, meaning that there is a separate "market without fees" rate.  The latter is the market you are in when using localbitcoins.  If you don't want fees, you'll pay a higher rate.