How big is the transaction you're trying to make (in bytes)?
I suggest to Enable coin control features (under Options > Wallet), select your own inputs, and create several smaller transactions. Take for example 10 inputs per transaction, set a low fee, and send it to one of your own addresses.
If your inputs are too low, say 10,000 satoshi or less, it's mose likely not worth the fee anymore.
The sum of the fees of many small transactions will be bigger than the fees of one big transaction...
At this moment, the optimal fee for a 95% chance of getting into the next 3 blocks is 162 sat/byte
For example, a non-segwit wallet having 100 unspent outputs:
10 transactions spending 10 unspent outputs at a time:
tx size per tx =~ (10 x 147) + (1 x 34) + 10 + 10 = 1524
tx fee per tx = 1524 x 162 = 246888 satoshi's
tx fee for 10 transactions = 2.468.880 satoshi's
1 transaction spending all 100 unspent outputs at once:
tx size =~ (100 x 147) + (1 x 34) + 10 + 100 = 14844
tx fee for this transaction = 14844 x 162 = 2.404.880
So, in the end, you'd pay an extra 64.000 satoshi's, and you'd end up with 10 unspent outputs instead of one if you decide to split up the one big transaction into 10 smaller one's.